getNonce

abstract fun getNonce(): Int
The identifier for an internal transaction that was spawned as part
of handling a user transaction. (These internal transactions share the
transactionValidStart and accountID of the user transaction, so a
nonce is necessary to give them a unique TransactionID.)
An example is when a "parent" ContractCreate or ContractCall transaction
calls one or more HTS precompiled contracts; each of the "child" transactions spawned for a precompile has a id
with a different nonce.
int32 nonce = 4;

Return

The nonce.