IT MUST BE GETTING CLOSE TO Super Bowl time. The Chicago Bears have reinstated Jim McMahon as their starter at quarterback for the first time in more than two months, and Chicago Chaos is back in style.

Bears Coach Mike Ditka on Friday named McMahon as his starting quarterback against the San Francisco 49ers in the NFC title game today in Chicago's Soldier Field. It will be McMahon's first start since Oct. 30, when he injured his knee.Ditka, true to his love-hate relationship with McMahon, announced McMahon as today's starter only reluctantly.

"Jim's the healthiest," Ditka said in explaining his decision. But the coach added that "it's a tough thing on Mike Tomczak. Mike wants to play very badly, but I don't know if he can take a hit."

Tomczak replaced McMahon in November and recorded a 4-1 record as a starter, compared to McMahon's 6-3.

That was enough ammunition for Ditka, who has never coexisted peacefully with McMahon. When the Bears won the Super Bowl three seasons ago, Ditka and McMahon weren't speaking.

But Tomczak had too much pain in his shoulder, and it was affecting his delivery, and even Ditka couldn't risk an NFC championship on that.

Besides, McMahon is 3-0 lifetime against the 49ers. Tomczak is 0-2.

In Tomczak's last start against the 49ers - last season in the playoffs, when McMahon was injured - San Francisco won 41-0 and Tomczak threw four interceptions.

This prompted McMahon to coin a nickname for Tomczak: "Lotto." The nickname was in reference to the Illinois lottery game: "Pick 4."

Not that McMahon and Tomczak aren't friends. According to newspaper accounts, McMahon invited Tomczak to his home on New Year's Eve last weekend, and everyone had a good time. No punches were thrown among teammates, or any of that jazz.

It would be hard not to have respect for Tomczak, who, fueled by that 41-0 loss to the 49ers a year ago, worked overtime on turning himself into a better NFL quarterback.

Tomczak hired a psychiatrist - so he could better deal with Ditka, and with McMahon.

And, last spring, he opened the First Annual Mike Tomczak Training Camp, with an invited attendance of one: himself. He hired a coach to help him and worked industriously on his mechanics. He charted out typical 80-yard NFL drives and marched up and down the field all day long, making sure he was throwing passes while his heart rate was at 185 beats per minute.

When McMahon's knee gave Tomczak a chance this season, he unveiled a new and improved model.

Ditka's eyes immediately lit up. As the Chicago press reported in a story this week, "There was always speculation that Ditka wanted to prove he could win a Super Bowl without McMahon, who is always in the midst of some controversy."

McMahon, incidentally, is in the midst of controversy.

For one thing, he's not speaking to the media. (His only audible response at training camp after being named the starter against the 49ers was to head for the shower whistling, "Back in the Saddle Again.") And while not talking to the press isn't such a big deal, McMahon's also getting flak from the Chicago radio station that hires him to do daily reports. They say he's dull.

According to a story in the Baltimore Sun, Rick Lippincott, the operations manager for station WLS, said, "We pay McMahon a lot of money (a six-figure salary) to tell us how he feels. His effort lately has been to yawn on the air. A lot of our listeners say they find him boring."

McMahon's response: "If he wants to fire me, let him fire me. If I've been that bad, then he's kind of stupid to let me sit here and take the cash."

It appears all is back to normal with the Chicago Bears, at least back to the normal of 1985. Willie Gault and Wilber Marshall may be traded, and Walter Payton and Gary Fencik may be retired, and The Fridge and Otis Wilson and Richard Dent may be injured and out of the lineup, but Ditka is back from his heart attack, and McMahon is back from his exile.

The 49ers should be concerned. It was precisely this way that the Bears of '85 found their way to the NFL championship.