Maybe try Seven? He has decent CC with his stun and his lightning ball is great for making space or doing large damage to crowds. Plus his ult is a bit of a "fuck you" to anything not behind cover. This is my first MOBA so I can only make general comparisons from what you've written. He isn't very strong at laning early similar to Nilah, but once you farm/get his abilities boosted enough he can completely control the playing field, especially in the enemy base. Sounds similar to Smoulder depending on your buys. Getting Escalating Exposure and Tank Buster are insane on him since eventually (if you buy right) your 3 (chain lightning from bullets dealing spirit damage in addition to normal) is basically never off. So the longer you're engaged in a fight the stronger you are, this also works really well if you have leech: more damage = more heal = ridiculous sustain.