The pair appeared together on 'The Tonight Show.'
While co-hosting The Tonight Show Starring Jimmy Fallon on Thursday, Megan put Natalia through the ringer with a hilarious line of questioning about how Nancy has navigated her relationships with Steve (Joe Keery) and Jonathan (Charlie Heaton, whom Dyer is dating in real life) -- and even her late BFF Barb (Shannon Purser).
"At first you liked Steve -- you was into Steve," Megan begins. "Then, you just kinda like dumped him. No caution, he didn't know what was happening. Poor Steve! Y'all keep throwing the kids on him, the babies, he keeps savin' y'all's life. All he do is save y'all's life. He was beating everybody up. She's like 'Aw, man, I'm going to Jonathan's. Sorry!"
Without pledging her own allegiance to "Team Jancy" or "Team Stancy," Dyer attempts to at least justify some of Nancy's choices.
"I think the way that Jonathan and Nancy happened, she doesn't always make the most morally right decisions all the time," Dyer says. "But that's human, you know."
Megan, calling Nancy "a hot girl," then calls her out for flirting with Steve in season four while still in a long-distance relationship with Jonathan. "What's it really giving?!" Megan presses. "I feel like you like Steve, still."
"I have options, I guess?" Dyer replies with a laugh before Megan turns up the heat further by bringing up whether Nancy even misses Barb, who was killed in the show's first season.
"That's above my pay grade," Dyer jokes. "I never am allowed to forget about Barb. I get it. It's part of Nancy's arc, it definitely drives her forward. Has she completely dealt with it? I don't know. But, yeah, we have not forgotten about Barb."
As for making a choice between dating Jonathan or Steve in the future, Dyer thinks Nancy should just take a breather.
"I think she probably needs a little 'me time,'" she says. "Maybe a little therapy, even. They're still in high school."
Stranger Things is streaming now on Netflix while Megan's new album, Traumazine, dropped Friday.