Since I just finished up my Plague Titan I figured I should write up some proper stats for him. I used the Forgeworld Warhound Titan as a starting point and went from there. I used mostly the same stats except I added a point of armor to the side and rear, but removed the ability to move during the shooting phase to balance it out. Slow and tough - the way Nurgle should be.
I also swapped out a few guns with the Nurgle Plague Tower. They are basically the same - just different names for the most part.
Here is a link to the PDF.
Test it out in an upcoming Apocalypse game and let me know what you think.