I've been watching the #nettle:matrix.org room, and it seems Nettle will be rewritten in Common Lisp. The consensus there is CL is faster than Python and will work just as well, except for finding libraries. This has seemed to be a nonissue, except the needed ECDSA code is not in Quicklisp. nettle-forum will be the first to be ported.

The output of the new libnettle provided by no-defun-allowed is:

CL-USER> (parse-nettle-object (format nil "Hello world!~%Hello children!"))
#<HASH-TABLE :TEST EQUAL :COUNT 1 {1003D11A73}>
 
CL-USER> (maphash (lambda (x y) (format t "~a => ~a~%" x y)) *)
Hello => (world! children!)

Really looking forward to this change if it happens. /f/nettle disappeared so I figured the information would be alright here.

Edit: here's the forum and the library.