I mained a Resto Shaman back in WotLK and I’d like to get back to him. Chain heal is my favorite healing spell in the game. I’m also a big fan of M+.
I looked up a bunch of guides and it’s a little overwhelming. My main question is, can I be successful in M+ with a chain heal focused build? (As opposed to a Riptide focused build)
Absolutely. There’s a Chain Heal focused M+ build on Wowhead that works great, I customized it a little bit for personal preference but as long as you’ve got the meaty chain heal talents on the right side of the tree then you’re golden. 
whatever build you pick you still gonna reptide . as a classic player you still had reptide in wotlk and cata