I don't think there were ever any comics based on the Next Mutation. If there were, none have ever turned up.
Closest thing is this fanclub booklet that Playmates sent out to members:
http://tmntentity.blogspot.com/2015/...ion-green.html
It's just character bios with production artwork, but that's as good as it gets. Wikipedia says there were some Venus de Milo text stories that were on the official website in the 90s, but were quickly purged when the show was cancelled. I dunno if those were ever archived or if they're lost forever.