The Hammers' skipper has scored five goals in his last four games after receiving two red cards in quick succession at the turn of the year.
Nolan found the net on Saturday as West Ham earned a 3-1 victory at home to Southampton in the Premier League.
"It shows what a character he is and how much of a leader he is within the group. The last few weeks his goals have been sensational for us and really kicked us up the table," Jarvis told the club's official website.
"He's very mentally strong, he got on with it and picked himself up but with the team we've got everyone got round him and it shows what a great team spirit we have."
West Ham's next game sees them entertain Everton in the Premier League on Saturday.