No suit: Lizard stomps.
With suit: Stalemate
Lizard cant damage Killmonger through the suit, and doesn't know about what removing the necklace can do. Killmonger still spends the entire fight getting ragdolled, and he can't really do any damage to the Lizard that it wont heal back from near instantly. Neither can really take out the other here.
Originally posted by FrothByteThat's definitely a possibility too. Either way, strong edge to Lizard
Even with the suit, the panthers seemed to still feel pain given enough impact. I'm going to back Lizard here. Kilmonger's claws are too small to do any significant damage that Lizard can't heal from. It may take some time but eventually Kilmonger will get beaten up.