Is provisions for bad debts nominal account?

yeah may be because provision for doubtful debt is a reserve which has been created against the debtors which is an estimated loss and also the journal entry is

[Debit] Provision for bad and doubtful debts a/c

[Credit] Debtors a/c

and here this loss is debited and hence it can be treated as nominal a/c but while preparing trial balance it has a credit balance as its a liability