That's fair, but if you want to go this way, you'll end up grouping them together with wind, hydro and concentrated solar, as they're all based on spinning coils around magnets (or the other way around). While this categorization may be useful for some specialized engineering discussions, it's useless when talking about environmental issues. When talking climate, we care about pollution and emissions - both of which put nuclear in the same group as renewables.

(The one potential environmental aspect where "thermal plants" as a category is useful is that thermal plants need a heat sink to operate, which usually means a river or a pond. On the scale of climate issues, however, this is a negligible point that I haven't even seen brought up once by anyone.)