The Justice Department and a group of states proposed a raft of changes to the business practices of Alphabet Inc.’s Google — including a forced sale of the company’s Chrome web browser — in the wake of a landmark ruling that the tech giant illegally monopolized online search.

If a judge orders Google to sell Chrome, it could dramatically upend the multibillion-dollar online search business.

The spinoff would be a major blow to the tech giant and will likely kick off a legal fight with wide-reaching implications for its core business.