As I understand it, (His) Nobs is having the Jack of the same suit as the turned up card in hand - when the turned up card is a Jack is when the dealer gets 2 points for (His) Heels.
So N = Nobs =a Jack in hand that’s worth a bonus point for its suit matching the turned-up card (presumably not a 5 or a Ten or other honor card), and the physical card touching with verbal scoring would be:
“(First Jack combo-ing with the two 5s) fifteen-2, fifteen-4, (second Jack) fifteen-6, fifteen-8, (third Jack) fifteen-10, fifteen-12, (three Jacks) 3 of a kind for 6 is 18, (two 5s) pair for 2 is 20, (touch Nobs) one for His Nobs is 21.”
Three of a kind is 6 points, of course, because there are 3 unordered pairs in a trio of ABC: AB, AC, and BC.
When learning to score a Cribbage hand, do things in the same order and you won’t miss things (except dialing to notice 3 or 4 card ways to add to 15), touching the cards with your fingers can help too:
15s first, 2 points each
Combo runs (double run like JQQK = 8,
triple runs like JQQQK = 15,
double double runs like JJQQK are twice double runs for 16)
Triples (6 points, as 3 pairs) or pairs for 2 (or rarely, 4 of a kind for 12)
Runs in a suit
Any 4- or 5-card flushes for 4 or 5 points (crib must be a 5 card flush to score)
Check for His Nobs
You can’t have Nobs and have a Jack be the turn card, since if the turn card were a Jack that would be His Heels for the dealer. Unless you somehow had two Jacks of the same suit show up in the game due to accidentally playing Cribbage with a Pinochle deck.