Nashville is filled with wannabe country singers dreaming of getting onstage and hitting the big time.

But when Maren Morris arrived there in 2013, she had more modest goals: After a decade of touring the bar-and-saloon circuit in her native Texas, and recording three independently released albums to middling impact, she figured the best she could hope for was to get someone else to sing her songs.

“I wanted to be a songwriter,” she tells The Post. “So I moved into a really shady Craigslist house, with two roommates I didn’t know. It was squalor — I think that house is condemned now. In my mind, the biggest thing I could accomplish was to have enough hits to open my own publishing company. But I started missing the stage and missing being the voice on the songs I was writing.”

I consider it to be a gateway drug to country! - Maren Morris on her 2015 album

So she returned to the stage, playing small showcases around town. The shows created a buzz on Music Row, and Columbia signed her in 2015, releasing her major-label debut, “Hero,” the following year.

“I consider it to be a gateway drug to country!” she says.

On Sunday, the 26-year-old is up for four Grammy Awards, including Best New Artist — and she’ll perform at LA’s Staples Center with R&B star Alicia Keys. Seems her plans for a publishing company are on indefinite hold.

Morris, who rocks a smooth yet strikingly powerful voice, is just part of a mini-country invasion at this year’s Grammys. Also up for Best New Artist (alongside Chance the Rapper, Anderson Paak and the Chainsmokers) is Tennessee’s Kelsea Ballerini. And Kentucky’s Sturgill Simpson earned a coveted Album of the Year nod for his superb “A Sailor’s Guide to Earth,” which will compete with Adele’s “25,” Justin Bieber’s “Purpose,” Beyoncé’s “Lemonade” and Drake’s “Views.”

Sturgill’s nomination shocked those who expected David Bowie’s final album, “Blackstar,” to take up one of the spots. Simpson seemed as bemused as anyone: Last month, his Web site began selling T-shirts reading “Who The F - - k Is Sturgill Simpson?”

While these names aren’t exactly familiar to those on the East and West coasts, they’re old news in the heartland.

“Maren has been playing bars and honky-tonks before she was even old enough to drive to them,” says J.R. Schumann, SiriusXM’s head of country programming. “It’s really exciting to see these artists getting recognized on a national scale. They deserve it, and it’s long overdue.”

The trio’s success signals a move away from the blunt, bro-country style of acts like Florida Georgia Line and Luke Bryan.

“My album has a few different colors to it,” says Morris, explaining the appeal of “Hero,” which shows proud gospel influences, especially on the single “My Church.”

Her fellow Grammy nominees also have feet in other genres. Ballerini’s 2015 debut, “The First Time,” reaches into pop — shades of the young Taylor Swift — while Simpson mixes elements of Stax Records-style R&B, and even covers Nirvana’s “In Bloom” on “A Sailor’s Guide to Earth.”

“I do feel that country kind of cleaned up at the Grammys,” says Morris, who’s dating country singer Ryan Hurd. “I think it’s going to be a very eye-opening night — especially for people who may not think they’re fans.”