To be more precise, NACS uses the Tesla physical connector but the CCS signalling protocol.
In consequence:
1: Cars with CCS Type 1 connectors can use a dumb physical adapter to connect to a NACS charger.
2: Older Tesla's (prior to ~2020 depending on model) need a $400 retrofit to be able to charge at non-Tesla NACS chargers. (The $400 retrofit includes a CCS Type 1 adapter, so it might eventually be cheaper without it).
To clarify #2: the retrofit is the newer controller board that speaks CCS. This is the same thing they've been offering as a "CCS upgrade". It's otherwise unrelated to the NACS switchover, though obviously those are CCS-protocol devices and thus work with it.
In consequence:
1: Cars with CCS Type 1 connectors can use a dumb physical adapter to connect to a NACS charger.
2: Older Tesla's (prior to ~2020 depending on model) need a $400 retrofit to be able to charge at non-Tesla NACS chargers. (The $400 retrofit includes a CCS Type 1 adapter, so it might eventually be cheaper without it).