Tonali started for Italy during both their Nations League matches against Israel and France this month, the former AC Milan player's first appearances for the national team since the Italian Football Federation banned him in October last year.
"I was pleased to see him play. He has performed well, those games would have done him the world of good," Howe told reporters on Friday.
"It's the first few steps for him, we are delighted he is available for us. Sandro has that flair and ability to make the difference. He is a player we absolutely love."
Howe said all his players who went out on international duty over the last two weeks have returned in good shape, including Brazil's Bruno Guimaraes, who was substituted after the first half during Tuesday's 1-0 loss to Paraguay.
However, forward Callum Wilson, who is out with a back injury, is yet to rejoin training, the manager added.
"Callum is a little bit behind where we want him to be. We envisaged he might be training for the games coming up, but he isn't there yet," he said.
Newcastle, who have seven points from three matches and beat Tottenham Hotspur 2-1 in their last outing, visit Wolverhampton Wanderers on Sunday and are looking to build momentum, Howe said.
"Performance wise, we haven’t hit top gear," he said.
"We have done well in different passages of each game but not consistently throughout the 90 minutes, that's what we're looking to do... because we are going into a spell where we are playing away from home now, some difficult games."