So we begin
1: Magnificent Buboes - 4 beers - 1 beer depending on situation
Ok. The Nurgle default spell is actually somewhat nasty. 5+ to cast, target takes a wound no armor save, 24 inch range with LOS restriction for the caster. In general this is going to be a champion sniper as Warriors of Chaos want to get into challenges with opposing characters. However if your opponent is running 3-4 Nurgle casters then it becomes a VERY dangerous spell for any characters. If the Nurgle sorc's controller is mainly targeting random models because he has no real target for it then don't worry too much, same if the target has a ward save of some sort. If there are 2-3 nurgle sorcs, then be careful.
2: Fleshy Abundance - 1 beer, almost 0 beers

Nurgle's second spell is not nearly as annoying to Dwarves as it is to most other races as we have very good access to flaming attacks. 7+ to make a unit within 18 inches of the caster regenerate until the beginning of their next magic phase isn't too much of a threat as it's main use is to prevent casualties. Our normal static combat res should be relatively sufficient. It's only really annoying part is that it's not a RiP spell. Dispel if the opponent doesn't have that many power dice left or he's using it on a hammer unit like a big knight unit.
3: Plague Squall: 1-2 beers
This spell is a funny spell, 8+ to turn the caster into a mortar shot that has the potential to damage a LOT of units because the template just has to TOUCH a model in the unit to hit the whole unit with 3d6 s1 no armor save attacks. It's the strength of the attack that makes it not really worthy of THAT much attention as he needs to roll 6s to wound most models in the Dwarf army. Plus he has the possibility of the template being centered on him if he misfires. Once again, probably not worth THAT much attention from Dispel Dice.
4: Cloying Quagmire: 10 beers
This is the KILLER spell for dwarves in the Nurgle lore: 9+ to cast, 24 inch range, LOS required to the caster. All models in unit take an initiative test and those that fail it (lots for dwarves) make an armor save and the models that PASS that test are removed from play. This spell has the potential to wipe out a massive number of models in a unit. Here's a bit of theory hammer here. 24 man unit is hit by the spell, On average, 16 models are going to fail the initiative test and of those, half are going to pass their armor save, more if the target unit is an Ironbreaker unit. You're looking at probably 8-10 casualties for a standard dwarf brick. Characters in the units are probably in worse shape. This spell is worth being hit by a spellbreaker every time and if you have a spelleater then try to nuke the spell completely.
5: Curse of the Leper: 2-4 beers depending on situation
This spell while it's a RiP spell is not really designed for RiP. It's meant to soften up a unit that you've just engaged with a hammer style unit. For example, if a basic warrior block gets charged by Knights and get this spell cast on them, that unit would be in real trouble. If the knights aren't Nurgle marked then they're hitting the Warriors on 3+ and wounding them on 2+ with their s5 magic weapons (as no self respecting Chaos player will pay 5 points a model for +1 strength on the charge and not magic weapons) and the warriors will wound back on 6s with their s2. This spell is worth throwing extra dice at it to make sure it doesn't go off.
6: Rot, Glorious, Rot!: 3-5 beers depending on situation
The final Nurgle spell has the potential to be VERY nasty depending on how the Nurgle player's casters are set up. 18 inch pulse from the caster for 1d6 s6 no armor save hits on all enemy units in range (even those in combat) AKA Cleansing Flare on Steroids. Depending on how the caster is set up, this spell could rock half your line before you get to do something if he goes first, especially if said caster is on a chaos steed and is moving 14 inches on the march in his turn.. If this spell gets spammed, it gets VERY ugly VERY fast. If there are multiple casters with the spell, then if it gets massively spammed, it's going to be NASTY. Dispel this if you have the dice, burn a spelleater if it's on a level 4 on a horse.
Here's an example of how nasty this can be. Situation was a Level 4 Nurgle Sorc on a chaos steed had it, and a level 2 nurgle sorc had it as well. Scenario special rule had a piece of fixed large terrain in the center of the board that gave the controlling wizard either +2 to cast spells or +2 personal dice. The terrain feature could be destroyed but it ended up not being so I had parked my level 2 in controlling position. The level 4 had been in a knight unit and got to a good position and got the spell off irresistably on turn 1 and hit 2/3 of the enemy line, killing about 5 quarrelers, half a bolt thrower crew and a bunch of warriors spread through units and instakilling a Gyrocopter. Over the course of the game I ended up getting the spell off 7-8 times killing a very high majority of the army. He still ended up with a draw though after skewering the knight unit with the sorc with a s8 bolt thrower flank shot after I missed overrunning off the board by 1/2 an inch.
These are my opinions of the Nurgle lore which I think has the most utility use of the 3 lores in the Warrior book. I'll probably do the new Tzeentch lore at some point soon as well.