Better way to reach Nyuto Onsen

we plan to visit Nyuto Onsen in winter February. Initially since we'd be visiting Hokkaido, we thought of departing from Shin-Hakodate Hokuto station but it'd take a very long time to reach Tazokawa station not calculating yet the bus journey to the onsen. Is there any other transit place to be recommended from Hokkaido to Nyuto Onsen ie. Tazawako Station?

We'd be back to Tokyo for our departure back home

Tazawako station is the closest station to Nyuto Onsen and it is served by Shinkansen. Apart from private helicopter I could not envision a faster way to get from South Hokkaido to Nyuto onsen.

Enjoy your winter onsen trip to Japan!

If, however, you are actually leaving from Sapporo, a flight to Akita or Hanamaki (the nearest airports) will be cheap.

https://www.world.jal.co.jp/world/en/japan_explorer_pass/lp/

thank You!
flying to hanamaki and akita is more efficient indeed! thanks

Are you sure that flying will be faster? In Shinkansen it is a little bit under 3 h from Shin Hakodate hokuto to Tazawako Station. While it seems to be about 1,5 h from Hanamaki airport to Tazawako alone. And about 3 h from Shin Hakodate to chitose airport. As far as I can see there are no flights from Hakodate airport to either hanamaki nor Akita. From Chitose airport there are 3 flights a day to Hanamaki taking 1 h. So even assuming that you are actually in Sapporo or Chitose flying is going to take longer than Shinkansen from Shin Hakodate Hokuto.
Just plan it out, and decide what works for you.

Enjoy your trip!

So even assuming that you are actually in Sapporo or Chitose flying is going to take longer than Shinkansen from Shin Hakodate Hokuto.

You underestimate how long it takes to go from Sapporo to SHH by train; it takes over three hours, for a total of about seven hours to Tazawako. From Sapporo, flying is a no-brainer.

yes, from Sapporo flying makes sense, but the OP is departing from Hakodate per her/his original post.

OP is looking at Hakodate, but asks if there are other options from Hokkaido, hence why I suggested flying from Sapporo.

Is there any other transit place to be recommended from Hokkaido to Nyuto Onsen ie. Tazawako Station?

from Shin-Hakodate Hokuto station but it'd take a very long time

3 hr train very long? Then, the OP should consider "armchair travel".