Question:
Is there a place to be מתיר cutting my nails- or at least chipped one(s)- on Hoshanoh Rabboh, if I didn’t cut them before Yom TOV started?
Answer:
The minhag of the Ashkenazim and some Sefardim is not to cut nail on Chol Hamoed if they weren't cut before the chag. the prohibition is oly when using an instrument ( nail clippers, scissors) to cut the nails, doing with your fingers or your teeth however is permitted.
Sources:
O:Ch 532 M:B 3.