2500 List (vs Nurgle Demons)

[BollaertN]

So, I am new to Warhammer in general, my typical lists are I believe not super competitive. After getting stomped by Demons into the ground I tried to create what I thought would be a more competitive list. I understand a few things in this list are sub-optimal, like the Sjiver's Hex Scroll... but I figured it might be worth it for the 33% chance to really knock out the Great Unclean One.

The scenario also kind of screwed me... Meeting Engagement, I had to deploy first, and my Supreme Sorceress was forced into Reserve.

Lords:
Supreme Sorceress, Level 4 Shadow, Talisman of Preservation, Sjiver's Hex Scroll

Dreadlord on Dark Pegasus, Gold Sigil Sword, Black Amulet, Other Trickster's Shard, Dragonhelm

Heroes:
Assassin, Cloak of Twilight

Master on Dark Steed, Dragonbane Gem, Sword of Might, Charmed Shield, Potion of Strength

Master BSB, Crown of Command, Enchanted Shield

Core:
5 Dark Riders, Shields, RCB, Musician
5 Dark Riders, Shields, RCB, Musician
15 Darkshards, FC, Shields, Banner of Flame
15 Darkshards, FC, Shields

Special:
RBT
RBT
20 Executioners
5 Shades, GW

Rare:
5 Doomfire Warlocks
5 Doomfire Warlocks

[MangoPunch]

Scary Things of Nurgle: Deamon Prince, Beasts, Plague Drones.

Things that Deamons hate: Light Council, Dreadlord w/ Black Amulet, Witch Elves with Flaming Banner, Ways to thwart their board control (Peg Masters).

My impression of Deamons is that they are fast and can hit hard - therefore you gun-line counterpunch list might not be ideal. Aside from that, there are a couple of clear sub-optimal choices (for competativeness):
1) Assassin - I am guessing you are putting him into Execs with the hope of fighting his DP - but there is no gaurantee he'll get the match up and he his fragile and you'd rather kill the DP before combat.
2) BSB - Crown of Command and no ward save. You should be aiming to keep him out of losing combats, and a lack of ward is dangerous when in combat. Maybe try Cloack of Twilight and a Dark Peg and Lance (a very popular build). You could also give your BSB Other Trickster Shard, and have him Join the Dreadlord in his battle vs Deamon Prince (have the dreadlord challenge, but OTS still impacts DP ward saves)
3) Gold Sigil Sword - Your dreadlord is lacking strength and relying on being in a challenge to do damage. Black Amulet is great on the DL to charge him into a wounded DP and reflect back wounds. I would either go BA and OTS (like you have) with a Lance, GW and Potion of Strength, or BA and Ogre Blade. He'll then be more formidable against not only lone characters (and more dangerous even against them.
4) No Dispell Scroll

If I were tayloring against Nurgle I would go:
1) Fighty Dreadlord on DP (like you have but modified)
2) Fighty BSB on Dark Peg with either a) Cloak of Twilight or b) Armour of Fortune and Other Trickster Shard
3) Level 4 of Light and 2 Level 1s of Light - and a big cheap infantry bunker with sacrificial dagger
4) A Block of Witch Elves with Flaming Banner
5) Lots of Chaff and some Shooting

[DA SAVAGE]

Just watch out for a unit of beasts other than that you should do fine. good luck! I have a 2400 against a Nurgle army later too.

[Enkiel]

If they have Epidemius, get him dead, quick.

Otherwise, beasts are better dealt with at a distance, since they can lock you in cc forever.
Fire isnt really required, since most of the time, the only regen is the Beasts.
Obviously, keep a bsb nearby, because a failed fear test, with the -1 to hit from nurgle, will ruins your day quickly.

[Akholrak]

+1 to everything MangoPunch said. In my experience, I find that Witch Elves with Cauldron slaughter Nurgle Daemons. Banner of the Eternal Flame could be good against Beasts, or if your opponent brings in a Herald with the Regeneration Locus. However, best watch to not get chaffed up by Furies or a single Beast. A third Bolt Thrower might be a welcome addition as Daemons have a few single model targets I.e. Single Beast, Greater Daemon, Soul Grinder. In addition, due to Greater Daemons only having a 5++ in terms of save, it could force your opponent to screen him or put him behind buildings, which keeps him from causing havoc in close combat. Also, I echo Enkiel's point. Kill Epidemius, and kill him quick. Those bonuses he gives really do come about quicker than you think. Hope this helps.