Seattle's Riq Woolen intercepted a desperation fourth-down pass by Chicago's Caleb Williams with 11 seconds remaining to seal the Seahawks' triumph.
Seattle improved to 9-7, second in the NFC West division behind the Los Angeles Rams (9-6), who will host the Seahawks on January 5 in the final game of the season -- one that could decide a playoff spot.
The Rams, who visit Arizona (7-8) on Saturday, can clinch the division crown with a victory and at least three wins plus a draw this weekend from among Buffalo, Minnesota, Cleveland, San Francisco, Cincinnati and Washington.
That would enable the Rams to seal the division crown and playoff berth on the basis of a "strength of schedule" tie-breaker advantage over Seattle.
Myers kicked a 27-yard field goal to give Seattle an early 3-0 lead, but the Bears equalized on a 42-yard field goal by Cairo Santos with 2:32 remaining in the second quarter.
Myers kicked a 50-yard field goal with 21 seconds remaining in the second quarter to give the Seahawks a 6-3 lead and it held to the end.
Chicago made a final drive in the dying minutes, kept alive when a scrambling Williams threw a 14-yard pass to D.J. Moore on fourth down, but three straight incompletions led to the pickoff to seal the Bears' defeat, dropping Chicago to 4-12.
"The defense was tremendous," said Seattle quarterback Geno Smith. "It was a hard-fought game. Our defense was lights out. They got the big play at the end there. They played great."
Hours before kickoff, the Seahawks placed top rusher Kenneth Walker on injured reserve due to an ankle injury suffered in a Sunday loss to Minnesota.
