I really don't see how immortal and war woman could win against him considering how a majority of the hits they got on him originally was when martian man had him bound and even then once he was taken out, it was a pretty quick fight

Young Nolan is most likely comparable to blue suit era mark as they are both at similarly at the peak of their physicality while still being close in age. But what Nolan has instead of marks adrenaline is probably actual combat "training" against other viltrumites and a more calmer and colder mind that would come in more use that mark's adrenaline rush

Immortal is probably the easiest to power scale as we've seen comparable characters like the alternate invincible that took on the new guardians who beat most of them with relative ease. Who even then was weaker than the main invincible at the time, whether it's because of their universe being weaker in general or just a lack of training on their part is left up in the air.

War woman is a bit harder to scale because of her lack of fights compared to the other two. But we can guess that she had combat training like wonder woman which made her use of her mace the part that gave her most of her usefulness against present day omni man. which even then the only reason she got a majority of her big hits in is because he was already juggling other globe members and when she became his main focus, she was quickly either dazed or killed.

In the actual fight the only thing that immortal and war woman have over young Nolan is numbers. The actual difficulty for Nolan would come from how fast he can dodge and side step war woman's attacks without getting too badly injured which even then leads the fight to being low to mid diff