I don't have a Nemesis, but I have a Mika and an Uncle Mike's #3 for my 642. I had a suede Nemesis that came with a S&W Bodyguard 380 but I just recently sold my BG380. I liked the Nemesis for that little pistol, I used it often.
I really like my Uncle Mike's #3 pocket holster for the 642. Honestly I use that more than the Mika. I would recommend it highly. Especially since it's only 13 bucks. For me the Mika is too bulky. I was debating on whether or not to go for the reinforced mouth on the Mika which comes standard on his holsters. After swapping emails with Robert Mika I went with the reinforced top because he described it as flexable. At first it didn't bother me but after comparing it to the Uncle Mike's it's annoyingly bulky in comparison. I hate to bad mouth Mika holsters because he is a great guy to deal with. I will probably order another from him in the near future but this time no reinforced top. Other than that he makes a great quality holster and I would definitely recommend them MINUS the reinforced top but that's just my personal opinion.