Continuity wrote:
I bet you can squeeze in another 5 man plague marine squad with double blight launchers if you take out the putrifier and trim out the upgrades on your plague champion, 5 plague marines with 2 blight launchers is significant firepower in 500 points especially when buffed with a chaos lord, while the putrifier scales heavily with plague marine squad size so he's not effective here.

Take a power fist on your lord if you have the points to spare, give him arch comtaminator warlord trait instead because he doesn't actually benefit from disgustingly resilient at all, that will give you 4 blight launchers that reroll 1s to hit and reroll all wounds, pretty horrific actually. You already gave him supparating plate so terminator army is not necessary, which gives you even more points to play around with.