nano - soft wrap at 80 characters

I would like nano to soft-wrap at 80 characters. That is, as I keep typing, the text should flow to the next line beyond 80 characters, without nano insert a \n newline at 80 characters. set softwrap set tabsize 4 set tabstospaces set fill 72 However, this inserts a newline after each line, when tested with cat. How do I softwrap and fill simultaneously?