I've recently really been wanting to attempt an RTS game, I think an NES style one would be really cool but there aren't any RTS games that were on the NES. Do you think it's too far out there or is it fine?

RTS as in Real-Time Strategy? How would you implement the controls? Might I suggest you go for a Turn-Based Strategy game? Like Famicom Wars.

There are a few, you can check Battle Storm (1991), and it wouldn't be a problem either way, some people nailed the NES feel perfectly with genres which were yet a bit anachronistic during the previous years.