Nancy and Sluggo were favorites of mine when I was younger. Somehow they have not yet reached the public domain. Likely due to the shenanigan's Disney and Warner Brothers pulled to get the public domain works extended. I've talked about this elsewhere.
However it seems the Fritzi Ritz comics, which are in the public domain, are allowed to use Nancy and Sluggo stories that were originally in their comic books.
Here's a sample.
One of the problems with the current laws concerning the public domain is that classic cartoons like this as well as stories and movies and TV shows are being forgotten. How does this in any way help the original creators? Snow White and Cinderella and other stories from the public domain may never have been known had Disney not taken these works and turned them into a franchise.
So how ironic is it that Disney is one of the culprits in the current ridiculous laws? Because they and others didn't want anyone to step forward and make use of their works after 75 years, they helped get it changed to 95 years and took away the possibility of other classics being turned into household brands.
Next time you watch a Disney classic remember this.