In a match that featured 24 break points, Nishikori was slightly more successful, converting four of his 14 opportunities against the world number 77.
Nishikori will face in-form Ukrainian Alexandr Dolgopolov in Sunday's final.
"It's really nice to be in a final again because I had a couple tough years," said Dolgopolov, who will be playing in his first title match in three years
News that makes sense
Your trusted source for staying up-to-date with the world around you. Get free daily news updates and analysis, straight to your inbox.
World number 66 Dolgopolov continued his barnstorming run through the tournament, beating fourth seed Pablo Carreno Busta of Spain 7-5 6-2 in the other semi.
Nishikori has a 5-0 career record against Dolgopolov, who has not dropped a set the entire tournament.
(Reporting by Andrew Both in Cary, North Carolina; Editing by Gene Cherry)
