I am a naturalized US Citizen and don't have a passport. Can I travel back to US from Mexico with my US Citizen Naturalization certificate and driver's license?
The US cannot refuse entry to a US Citizen, which of course you can prove you are by showing your certificate. That being said, they will likely have to verify it and that may take some time.
The US Dept. of State says:
If you are a U.S. citizen crossing into the United States from Mexico by land without a U.S. passport, you may be slowing down the lines and increasing your wait time.
If your license is an enhanced security document (referred to as RealID) then you can also use that.
Beware that if you are not already in Mexico, their guards have a right to refuse entry if you do not have a valid travel document (passport book or card). Though that is unlikely as I have friends who cross with just their RealID all the time.
That same page which is linked says:
The Mexican government may not let U.S. citizens who are driving or walking to Mexico enter the country at land border crossings if they do not have a U.S. passport book or U.S. passport card.