A "COVID specific nurse" still needs the entire slate of training that goes with respiratory disease, inflammatory disease, etc, and all the secondary complications that come from those.
Then train 3 nurses in respiratory disease, inflammatory disease, and secondary complications separately. Put them under an experienced nurse, and incentivize them to add to their skills when they're not working.
Look at the sheer difference in numbers of healthcare professionals between America and Cuba. If they can do it even after decades of cruel and unusual sanctions, we sure as fuck can too.