I think every chess player should learn this checkmate, it requires several techniques that are present in every day chess play like piece coordination, kings opposition, value of waiting moves, etc.
Although this checkmate is consider as a basic checkmate I think it is the trickiest one, in particular because of the 50 moves rule that will help the defender in case the attacker makes a few mistakes.
The best explanation I found about this checkmate is in the book "Fundamental Chess Endings" by Karsten Muller and Frank Lamprecht. There is an Amazon paperback version and a cheaper Kindle one.
This is a very well explained YouTube video about the KBNK checkmate https://youtu.be/oRK7XLhGz_c
The following link will allow you to practice against the lichess engine. The method they explain is called Deletang's triangles, from the name of the person that formalized it. https://lichess.org/practice/checkmates/knight--bishop-mate/ByhlXnmM/D23EYigW
Personally I prefer Phillidor's method using the Knight's W route.
At chess.com I use the following link to create a custom position and challenge people to play, that way I use the randomness that humans introduce in the game, it is amazing to see how many players don't know how to deliver checkmate, https://www.chess.com/variants/custom
When perfectioning your endgame technique I found the following link to tablebases online very useful: https://www.shredderchess.com/online/endgame-database.html
For example the following endgame requires 30 moves with perfect play:
Since August 2021 chess.com also provide the tablebase feature, see announcement: https://www.chess.com/news/view/chesscom-announces-new-tablebase-feature
(This is a work in progress)
