We used to believe Prime neutralized such but it’s been proven it doesn’t.
So the best bet is significant water changes.
The catch is to get more bacteria to grow you need the food for them. But nitrite is toxic.
If you have another bucket/container/tank and its reasonable to temporarily remove the shrimp, then I’d not do a water change and let the bacteria grow for a few weeks to consume the nitrite.
But if the shrimp stay in, I’d do multiple 50% water changes to get it low.
The other option is to buy/use a resin product (Seachem Purigen, costly) that absorbs it, but that’ll compete with bacteria and negatively impact getting your cycling more robust to handle it.
chaerrybun 
We used to believe Prime neutralized such but it’s been proven it doesn’t.
So the best bet is significant water changes.
The catch is to get more bacteria to grow you need the food for them. But nitrite is toxic.
If you have another bucket/container/tank and its reasonable to temporarily remove the shrimp, then I’d not do a water change and let the bacteria grow for a few weeks to consume the nitrite.
But if the shrimp stay in, I’d do multiple 50% water changes to get it low.
The other option is to buy/use a resin product (Seachem Purigen, costly) that absorbs it, but that’ll compete with bacteria and negatively impact getting your cycling more robust to handle it.
Add conditioner that removes nitrite like Prime and do a 10% water change.
I don’t know if it helps or works, but I saw ampules of bacteria at Petsmart that are supposed to help cycle a tank. Hope everything works out.
Small frequent water changes and a beneficial bacteria mix untill the tank is stable.
Try to remove any rotten matter
Like if a part of a plant died off which happens in new planted tanks.
And have live plants.