The striker scored the only goal in the Foxes' 1-0 win over Stoke City this afternoon to take his total for the season to three.
Pearson told BBC Sport: "To do well in any division you have to score goals and for Leonardo Ulloa to get three already is great for him.
"His all-round game gives us a focal point in terms of having different options. He is very popular among the players and he has settled in very well.
"The players are enjoying the Premier League so far. But you only truly enjoy it if you are playing well and getting good results."
The club broke their transfer record to sign the Argentine from Brighton & Hove Albion ahead of their return to the top flight.