Nichinan Gakuen is no stranger to Koshien, but they tend to go years between appearances and it's been a while since they've had a modicum of success. Furthermore, the resume is rather light as they didn't face any of the familiar teams out of Miyazaki, and then also got a favorable schedule in the super-regionals before finally running into Shounan in the quarterfinals, just eking that one out before getting routed by Shuugakukan.
With such a soft schedule it is hard to make any good analysis on their prospects. Ace Moriyama Genki (森山 弦暉) seems to be the guy they realistically trust in their big games, but I don't have any info on him (natch). His big problem seems to be getting out of the gate, having given up 7 runs in the first 2 innings of the semis and finals. Minoo Yuuki (蓑尾 優希), Ueno and Kurihara were used in relief, but again, not when they faced Koushien-level competition.
Offenseively, cleanup hitter LF Masuda Kaisei (益田 海成) was by far their most consistent hitter on the team, but you couldn't say look at the top of the lineup and see a decent set of hitters, and that is also concerning. This may mean that they only way they got a bit was because of their soft schedule.
Expect a one-and-done performance barring an easy pairing, and that's no gimme either.