Nineteen-year-old Usami last week sealed a six-month loan deal to Bavarian giants Bayern, with an option to make the move permanent should he impress sufficiently in the German Bundesliga.
While he still has a couple more fixtures to play for Gamba before he flies off to Munich, Usami showed a glimpse of what his current side will soon miss after scoring in their 1-1 draw with Urawa Reds on Saturday.
Speaking after the game, Nishino believes Usami has what it takes to succeed in European football.
"We are going to lose Usami but he has great potential and I want him to do very well," Nishino told The Japan Times Online.
Urawa themselves currently hold on to one of the unpolished gems of Japanese football in Genki Haraguchi, who also scored in Saturday's game, and Nishino predicts both players will go on to star for the national team.
"Usami and Haraguchi are surely both future leaders of Japanese football.
"They are both aware of each other and they influence each other.
"I could sense a very aggressive rivalry between them on the pitch."
Should he succeed in the Bundesliga, Usami would follow in the footsteps of a growing number of Japanese players to have made their mark in Europe, including the likes of Borussia Dortmund's Shinji Kagawa, Inter Milan's Yuto Nagatomo and Wolfsburg's Makoto Hasebe.