As someone who has spent a few holiday seasons around Chicago, Mila Kunis was concerned that “A Bad Moms Christmas” (opening Wednesday) “really look like it was shot in Chicago” — even though it was shot in Atlanta. “We had a wonderful production design team, but they were perfectly happy with us giving them tips — especially about what houses would look like in Chicago neighborhoods,” said Kunis about herself and other cast members familiar with the city. She and co-star Kathryn Hahn, a Northwestern alum, also made sure that scenes shot in malls “really looked like the ones I’ve been to in Chicago, and especially in the suburbs,” said Kunis, who has been in Chicago both as a visitor and to shoot the exterior scenes for the original 2016 hit “Bad Moms.” “I think they did a very authentic job,” added Hahn as the actresses chatted up the film in Water Tower Place the other day. When it came to this sequel, Kunis said, “we were so grateful that we wrapped filming when we did. Think about it. We were in Atlanta, pretending it was Chicago, but it was springtime, bordering on the beginning of summer. It’s a Christmas movie, so naturally, we’re all decked out in heavy sweaters, parkas, and all kinds of woolen clothing. “The good news: We got out of there before it really got hot and steamy, as Atlanta does in the summertime.” One of the main themes of the film focuses on many mothers’ desire to stage the perfect Christmas experiences for their families. In the case of Kunis’ Amy character, try as hard as she does, she never comes close to matching the overbearing perfectionism of her mother, Ruth (Christine Baranski). “I think a lot of moms will go to see this movie and hopefully realize they just need to relax. Who cares if your tree and decorations aren’t like something out of Neiman Marcus?! The holiday is all about family and having fun — and hopefully, that’s what we’ve put across here,” added Kunis. In “A Bad Moms Christmas,” we get to see three very different mother-daughter relationships. Along with the intense Amy-Ruth conflicts, Susan Sarandon plays Isis — a pot-smoking free spirit whose relationship with her daughter Carla (Hahn) is more like that of a