Trim the ends of the corn without removing husks. Microwave corn 3 minutes. Let cool. (This step is optional, but makes the corn easier to shuck and cut.)
Chop onion. Heat oil in pan, add onion, saute until softened.
Chop tomatoes. Shred basil.
Being careful of any steam, remove husks and silk from corn. Cut kernels from cobs. Add corn to pan, saute one minute (3 if you did not parcook it in microwave.)
Add tomatoes to pan. Saute until tomatoes just start to soften and release liquid, and both corn and tomatoes are heated through.
Add basil and stir to heat.
Serve.