Johnny Nicholls was one of a pair of insolent maintenance men who caused trouble for David Barlow at Sid Lambert's social club in 1965. Employed at Lambert's engineering firm S Lambert Ltd, Johnny and Tony Gordon clashed with David when he, in his capacity as sports and social officer, hired Len Fairclough to put up shelves in the club bar rather than have the work carried out in-house.
The men's first skirmish occurred when David caught Johnny helping himself to the bitter in the club bar. Johnny had poured pints for himself and Tony when Joe the barman refused to serve them outside licensing hours. As he hadn't finished his drink yet, Johnny stood his ground and was incensed when David took the glass and poured it out. The men backed down when David threatened to report the matter to Sid. Later, they returned to discuss the work Joe needed done, and learned that David had switched to a professional contractor, when before they had done all the odd jobs. Johnny suggested that David had taken a backhander from Len, bringing up a bribery scandal David had been involved in earlier that year, even though, as David pointed out, he was subsequently cleared of accepting the bribe.
Deciding to get their own back for the slight, Johnny and Tony got tickets to the upcoming social club dance from Joe. At the dance, Johnny made a play for David's fiancée Irma Ogden, having a go at Dennis Tanner for scaring her with a gag spider. Later, while David was dancing with Irma, Johnny pinched her bottom, causing David to nearly lamp him. Johnny asked to see David outside to settle their dispute the old-fashioned way, but the arrival of Sid prevented the situation from escalating further. Johnny and Tony looked on smugly as David received a stern rebuke from his boss for his heavy-handed response to "a bit of fun". This bolstered Johnny to make a play for Irma again, asking her for a dance, only to be told to drop dead by a cheesed off Irma.
- Credited as "Johnny". The character was given a surname in dialogue in Episode 484.