There's no law that says he needs to work with the Protectorate to do anything! The Protectorate is just very, very good at navigating the laws and bureaucracy that regulate commercial parahuman activity, and it is happy to help parahumans who cooperate with it.
As to the actual law, well, NEPEA-5 was written with the express aim of driving capes out of business and into the Protectorate's arms. And it absolutely worked as advertised! (Don't ask us about any collateral or counterfactual costs.) It is broadly speaking illegal, without government registration-and-licensing giving explicit approval, for capes to:
1. Benefit commercially from their powers, in a way that materially hurts either the bargaining power of human labor or the pricing power of companies employing human labour. (There is an explicit carveout for non-profits.)
2. Use powers to predict or affect markets (broadly defined) to their own or someone else's benefit.
3. Offer products or services which do not or cannot provide the same legal assurances as would be required from human-produced equivalents. For example, a Tinkertech radio cannot be sold because no human can certify that it obeys FCC regulations. A Tinkertech factory producing (ordinary, non-Tinkertech) cement cannot sell it because no human can certify that the production process conforms to EPA emissions regulations. Et cetera.
4. Claim to customers (or to the courts) that a power-produced product or service definitely does or does not have some quality that no human can verify. For example, you cannot take people's money in exchange for foretelling the future with your Thinker powers.
5. Use powers to fulfill a legal obligation in a way that no human can verify. For example, if the law requires a transcript of some conversation, you can't use a Tinkertech transcribing device; you have to employ a human secretary. If the government requires you to file five hundred pages of forms, you can't use your Thinker powers to fill them in while watching TV and then sign at the bottom.
And so on, and so forth.
That is, you can't do any of those things unless you work with or for the Protectorate, because they're a government organization (not to mention a paramilitary one) and so have all the necessary exceptions written into their establishing act.