The Gunners have been hit by a double midfield injury blow, with Mikel Merino out for the season and Kai Havertz to miss a month.
Asked if he regrets now sending midfielder Nwaneri to France last month, Arteta said: "It's easy to say in hindsight. When the decision was made, no one could have predicted that Mikel would be out for five months and the same with Kai."
Arteta explains that the club must make decisions based on the current situation.
"It is unfortunate, but ultimately we have to make the decisions based on the situation here and now, with an understanding of the context we are in, and what is best for the club and for Ethan," continued Arteta.
He also believes that the loan was the right step for Nwaneri's development.
"For him, it was clearly the right decision to come out and experience a different environment, get playing time and get ready to return to us."