Hey, yeah, PuTTY and Terra Term come up a lot since they’re common on Windows, but on Mac, there are actually some decent options too.
If you're sticking with serial stuff, the terminal inside MCUXpresso IDE works fine, but a few others are worth checking out:
CoolTerm is simple and does the job
Serial.app is a bit more polished (though it’s paid)
iTerm2 with something like screen or minicom is solid if you're comfortable in the terminal
Attune is great if you’re doing more complex scripting or automating things across machines
Termius is pretty user-friendly and works across platforms
Zoc is another powerful one (also paid, but has a lot packed in)
Totally depends on what you’re trying to do — simple serial vs full-on automation. Sounds like you’ve got things working now with MCUXpresso, though, which is great.
Hope this helps if you want to try something else later.