Even

Whatever bad things you do to me, it’s [color=darkred]even nice to forgive you.

Is it correct?

It is odd. “Even” usually occurs where there is some element of surprise, however slight or strong. Of course, it’s nice of you to forgive the person.

They stole everything, even the kitchen sink.
He said terrible things to me. He even said he never loved me.
Sally is generous. She literally even gave me the shirt off her back.