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As far as I know, the only way to disable this is by setting a Firmware Password.

Here's the Apple article that says the key combo does nothing or enters recovery mode:
https://support.apple.com/en-us/HT204063

Here's the Apple article about how to set a firmware password:
https://support.apple.com/en-us/HT204455

Extremely important advice: write down any firmware password you set, and store it in a safe place you will remember. If you forget the password, you'll have to take your computer into an Apple Store, and bring proof of original purchase.

Note: If your Mac is too old to set a firmware password, then there's no way I know of to disable the resetting of NVRAM / PRAM.
 
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