How do i replace vim with nano?

I tried replace in .bashrc but didn't work.

Post your ~/.bashrc (it should default to neither of the above, micro is default in KaOS for quite some time now).
Any change to ~/.bashrc needs a logout/login to take effect.

I did that but didn't work, i will stay with vim

Without posting your bashrc, not possible to help, ofc it will switch to any desired editor if you edit correctly.