So I'm at the fight with nicole with 23 pulse rifle rounds and no stasis, did I just lose to dead space 2?

NO. you won't. DS 2 boss fight is much easier than DS 1 monster. it's just one bitch with several packs. jsut focus on destroying marker. it's just right in front of you. so it is easy to do. by the way, keep some distance to nicole, if you are closed to her, you will be died. see for youself what will be happened if you wonder.

" So I'm at the fight with nicole with 23 pulse rifle rounds and no stasis, did I just lose to dead space 2? "

" NO. you won't. DS 2 boss fight is much easier than DS 1 monster. it's just one bitch with several packs. jsut focus on destroying marker. it's just right in front of you. so it is easy to do. by the way, keep some distance to nicole, if you are closed to her, you will be died. see for youself what will be happened if you wonder. "

If you kill some of the pack they drop ammo.

I had more ammo than that, and I just eventually gave up.  The sad part is when this happens to me in games, I usually just never end up going back to them.

I can top that perhaps.  I'm at the last boss on Zealot with zero ammo for any gun (technically I only have the plasma cutter tho), no health packs, but like 50 stasis.  
 
I tried stasising her and punching her.  That works but when the Marker opens up I can't hurt it.  So Then she reappears with all those little creatures (they drop ammo so i tried punching them to death) but no amount of stasis can save me from death at that point.  I gave up for now...gonna have to do something about conserving my ammo through the gauntlet of bullsh*t prior to the final boss.  I have zero credits to buy anymore ammo or health at the store, however.
 
edit: Went back a save and sold everything in my inventory.  Tons of plasma cutter ammo now...still doesn't help me tho because I get overrun by those shadow monsters.  Definition of cheap as opposed to hard imo.  Spawning enemies in a circle around you....Nicole, herself, has literally spawned on me 3 times which is instant death.

I ran into the same situation. I used the Javelin Gun, which I had literally never touched before the boss fight. If you run from the pack of shadow monsters, gather a good group of them behind you, shoot a javelin in the middle of them, and then use Alt-Fire to electrocute all of them, it takes out a good bit of the pack while using only a small amount of ammo. It also works well when shooting Nicole, as you can Javelin+Alt-Fire her and take her out in a few hits. Save up any ammo picked up from the shadows, and use that to take out the Marker.

Took me about 5 goes to beat this boss even with plenty of ammo - seems like it could be broken for you people, those enemys DO drop plenty of ammo though but it's tough. 
 
I ended up deciding to only fire at nicole - 9 shots from my plama cutter makes the marker vulnerable (and kills all of the pack) so i then reload whilst that is happen and then switch to my plasma rifle and lay in to the marker, as it begins stabalising i reload and then switch back to the cutter, rinse, repeat. 
 
I enjoyed the boss fight in ds1 much more.

force gun 1 shots the shadow pack monsters on normal difficulty, so i recommend using that