The Dutchman joined Bournemouth from Stamford Bridge in the summer, and will face the Blues for the second time of the season on Wednesday night.
"He felt he was at a stage of his career where he needed to play regular football to improve and to reach the levels he wanted to," said Howe.
"The aim of him and every player will be to play as high as they can. I don't see any reason why that wouldn't be possible for Nathan in the future.
"He has no point to prove because he did not leave under that situation. For him, it was a case of wanting to play more regularly. He will want to go back and perform well but I don't think he has anything to prove to anyone there.
"Chelsea were reluctant to let him go and were not keen to see him leave but were understanding of Nathan's situation in his career.
"They reluctantly agreed to let him progress his career. Maybe we were surprised we did not have to fight off more clubs to get him but were delighted he chose us."