Both are terrible cards honestly. Why would you use Beltran Cr when you can use Jeto? Are you gonna spend more than 4 pillz on Beltran Cr? If not, Jeto will always have a higher attack. There's also Treeman who can gap better and can be used any round, Flora if you want to heal (I personally don't use her as 5 power is horrible, but you can if you want), Willow for practically the same purpose, Miken Moose for even more attack with less pillz. IDK, I don't see the appeal. He was probably very good back then when there wasn't much else to play
Nahi Cr has that very awesome 2 damage! Wait, that's a bad thing. Opponents usually won't care and just let you go through for 2 damage. I mean unless you're really afraid of Skeelz for some reason, why would you use her? She seems good on paper because she can stop your opponent's bonuses and has a relatively high power but seriously, no one will bother stopping the 2 damage. Again, was likely very good before stop: abilities were introduced, but now, not really.
Well, I'd look for Nahi Cr to stop cards big cards like El Davino, Lizbeth, kinichaw, or Oflgn. You could even sacrifice her on like a Gil, sigma or Hula bc they'd be rendered useless
and Beltran Cr I feel is just not as good as Jeto or micken moose. Maybe if you really wanted a 8/2 2* but I don't see the appeal either.
I don't see Nahi as a bad card at all. She's an all stop with respectable power and a low star count. Not only shes an effective wall that keeps nasty abilities from getting through. I use walls a lot different than other players, and I don't play them and pill the crap out of them, most of the time I just 1 or 2 pill them and see what happens, its only one round lost and with Nahi you peg the enemy down to just basic power/damage every time.