Pose is looking alright
The jaw is looking a little wonky, and from the pictures looks a bit too far forward. I'd mostly just advice cutting the chissel chin down a little, and using it a base for the teeth then skin.
Bloated belly isn't bloated enough
Most daemons of Nurgle seem to be designed more with a fat appearence in mind, rather than just stomach bloating. Bulking up the belly, and allowing to droop down like rotting flesh would, would be a good idea.
At the moment, the green stuff on the back heavily reminds me of the Headcrab Carrier zombie from HL2 onwards, but the wings don't seem to be coming out the right way. By that I mean it doesn't look like there is any missile or ligaments attaching them. I fully undertsand the chaos of chaos, but even from what we seein models, artwork and read in fiction, they do still follow a degree of correct anatomy. Had I seen the project earlier, I would of adviced creating the muscle and anatomy correctly, and then add the pustules and rot on top.
The shield looks a little bit too early to really say much on unfortunately
Most I'd say is working with plasticard in layers may have been a better choice, over using a model base. The Fly sigil could easily have been replicated with Plasticard with a sharp hobby knife. Though the premade detail is obviously hard to ignore.
Overall, it certainly has the feel of a WiP Nurgle Daemon Prince, but in short I'd say you need to work on your anatomy, rot and bloat.