I use tcc with Nim all the time and it yields almost interpreted REPL-like code-iteration speed (like 100-500ms per compile-link - almost ENTER-see-results).
As a warning, you need to be sure --lineDir=off in your nim.cfg or config.nims (to side-step the infinite loop mentioned in https://github.com/nim-lang/Nim/pull/23488). You may also need to --tlsEmulation=on if you do threads and you may want to --passL=-lm.
tcc itself is quite fast. Faster for me than a Perl5 interpreter start-up for me (with both on trivial files). E.g., on an
i7-1370P:
Does V still just output C and use TCC under the hood?