The striker hasn't scored in almost a month for the Premier League side, who are experiencing a dip in form.
As the Blues look to take on Bournemouth in the league on Tuesday, Maresca was asked about Jackson’s form and confidence.
He stated: “Just to continue to work in the way he is working. As you said, he scored many goals at the beginning of the season. Now, there are games where he is not scoring but we are completely happy with Nicolas.
"We don't judge Nicolas just because of the goals. We judge Nicolas for different kinds of things and as I said already, I spoke with Nicolas a few days ago. Last year I think he scored 14 or 15 goals in the Premier League without penalties. (Erling) Haaland, penalty, (Mohamed) Salah, penalty, Cole Palmer, penalty.
"If you score 14 or 15 goals in the Premier League and you have four or five penalties, no more than that, then in the end it is 20 goals for a striker. This year, he scored already nine or 10 goals. For Nicolas, he is doing well, he is scoring goals with us without penalties and that is not normal for a No.9. Normally No.9s have penalties. We are completely happy with Nicolas.
"For sure, he is going to score goals. Also he is a bit unlucky because in those games he didn't score, he had great chances to score. Sometimes you will score but he has to continue in the same way."