This is a good comeback fight for Okada who has lost two in a row albeit to good competition in America. Tomioka is a decent domestic fighter in Japan who has had mixed results when fighting the best domestically.
Hiroki Okada is a decent technical boxer who has respectable power. In Japan he mostly dominated the domestic opponents he faced and only lost when stepping up to the International stage. He has been stopped twice however those were versus bigger punchers than Tomioka.
Izuki Tomioka is a decent domestic fighter but isn’t as experienced as Okada is. They’ve had mixed results versus other domestic fighters however all of their defeats were close and at the time of their stoppage losses they were very close on the cards or even ahead in one case.
I think Hiroki Okada should be able to win by stoppage due to his experience and superior power as Tomioka isn’t a big puncher by any means. I also think that unless Okada has lost a step that he should still be good enough to beat most domestic opposition in Japan.