How can you reach chuck in Pokemon Silver?

You can't reach Chuck in Pokemon Silver. He is only found in Pokemon Gold.

However, if you are looking to challenge a similar gym leader, you might be thinking of Jasmine, who is the Steel-type Gym Leader in Olivine City in Pokemon Silver. You can reach her by travelling south from Ecruteak City, crossing the bridge over the ocean.

Let me know if you have any other questions about the game!