I did few years ago a relation to WH to WM to chaos armylist. My manual is The Lost and the Damned. Well I know it is quite old book, but still one of my favourites of GW.
This book gives 4 armylist:
mortal army of nurgle --> WM mortal chaos in basic rulebook
daemon army of nurgle --> WM daemons
mortal army of Tzeentch --> WM mortal chaos in basic rulebook
daemon army of Tzeentch --> WM daemons
As I do not have daemon army I will focus in WM mortal chaos. I use it for taking ideas to add figures to the standard types of troops. I like the idea because the WM marauder figures are quite difficult to paint

The equivalent of new figures to represent basic WM troops/regiment in a army of mortal chaos devoted to nurgle (according Lost and the damn) are the following:
WHF --> WM --> figure suggeston
· Chaos warbands --> marauders --> GW
· Chaos knights --> knights --> GW
· Chaos warriors --> warriors --> GW
· Chaos Thugs --> marauders --> pendraken beggar army with nasty conversion??
· Beastmen --> marauders --> Pendraken beestmen and Eureka
· Chaos warrior of nurgle --> warriors --> GW with colour scheme paint
· Plague knights --> knights --> GW with colour scheme paint
· Diseased flagellants --> warriors or marauders?? --> GW flagellant figures with colur scheme paint
· Pestigors --> Ogres --> Eureka
· Chaos spawn --> chaos spawn --> GW
· Pack of chaos hounds --> hounds --> GW
· Cavalcade --> a representation of nurgle flying circus to work as a indicator for a banner or magical object --> only one base transparent for the game. Made of those figures badly sculpted for irregular pendraken and some GW plague bearers
· Trolls --> Trolls --> GW
· Plague cart --> ?? --> Pendraken grim reaper on chart
· War altar of nurgle --> could be a hero or magical object recall marker --> ??
· Mob of nurglins --> hounds or marauders? --> GW daemon figures
· Plague skeletons --> marauders --> GW skellie infantry
· Plague zombis --> marauders --> GW zombis or pendraken zombis
NOTE: for the game the stats used are the ones in WM chaos list, so plauge skeletons has marauders stats and works as them, with reaction moves and so on. It is only a way of making a little bit customize and colourfull army, and having fun painting and converting.
Also made the same for Tzeentch, if someone of you are interested, just ask for it and I will type it in here.
@Fracas, it is close to what you are asking for?