Nuke Indie is $499 annually, not monthly. It's vastly more competitive for single-person shops than the full Nuke offering is (although there are some significant limitations around resolution (4K) and scripting/third-party plugins).
Nuke Indie is based on Nuke Studio, so it's comparable to Fusion + Resolve.
Nuke arguably leads on some of the basics like paint and tracking, has much better multichannel support, and has much saner color management. Nuke has a big community at Nukepedia behind it, with all kinds of free gizmos. I know how unpopular this term can be here, but it's the industry standard for compositing, and if you want to work as a compositor, you have to know Nuke.
Fusion has some great ideas, too; it's pretty fast, it's resolution independence is really neat, and it's got a nice, fast, flexible 3D space. The biggest differentiator? Fusion has Blackmagic Design. If you're already into Resolve, or if you are price sensitive, it's a great choice. (BMD's storied pace of development remains to be seen as a strength of Fusion.)
I think that Nuke Indie is meant to be an on-ramp for people to the larger Nuke ecosystem, moreso than an actual standalone product. Some of the biggest benefits of Nuke over Fusion is on the pipeline side, but that's a non-starter with Indie because there's no scripting. Nuke Indie files are encrypted and cannot be read by standard Nuke licenses, so collaboration isn't possible.