Nike’s swoosh is being flipped into a frown as it takes a pounding from Under Armour on all fronts.

Last week, we warned you Nike was facing competition from Apple for the former 40,000-square-foot FAO Schwarz space at the GM Building at 767 Fifth Ave., both for a temporary and permanent location.

We learned over the weekend that Under Armour — Nike’s athleisure and branding nemesis — is also trying to elbow the company to the sidelines.

UA Chief Executive Kevin Plank said in January that the Baltimore company plans to open 200 stores this year — 100 of them in China — and now wants to flesh out the former toy company space to create the perfect “brand house” backdrop for its visiting celebrities.

In another example of the upstart pressuring king-of-the-hill Nike, Under Amour and UCLA on Tuesday revealed a $280 million, 15-year sponsorship deal — the largest ever in college sports branding.

UA has also been giving Nike a bit of agita on the athlete-sponsorship front. Plank has under contract perhaps the best athletes in three sports, basketball’s Stephen Curry, golf’s Jordan Spieth and football’s Cam Newton.

UA even has prima ballerina Misty Copeland pitching its product.

On the commercial real estate front, Nike has its outdated high-school-like store in the Trump-owned 6 West 57th St., where it can remain until 2022.

But the Phil Knight-controlled sneaker giant has been exploring other possibilities.

It missed out on the former H&M space at 640 Fifth Ave. that Victoria’s Secret grabbed. It is also building out the interior of its new 61,000-square-foot Soho store at 529 Broadway.

Meanwhile, UA opened its own huge Soho location at 583 Broadway in a deal we first told you about in October 2013.

The companies either declined comment or did not return requests for comment.

Parrotheads rejoice. Margaritaville may be heading to Times Square’s Brill Building thanks to its cutting a deal with the landmark building’s new owners, who take control next week.

We hear that Jimmy Buffett’s entertainment restaurant concept could soon change that northwest corner of West 49th Street and Broadway into Parrothead Way.

If it comes, expect a multi-level restaurant and shop at the street level for all the land sharks, as well as a unique outdoor experience on the top of the 11-story building.

The rooftop alone has 12,700 square feet and includes a patio area where folks will be able to chow down on a cheeseburger in not-quite-paradise.

The sale of the building at 1619 Broadway — to Ilan Bracha and Haim Binstock ’s B+B Capital and partners that include Conway Capital and others — is due next week with a slight pricing boost.

That’s because it took a while for the sellers, Eric Hadar’s Allied Partners and Brickman & Associates, to get City Landmarks approvals to include a special, three-story LED sign. The sign will be used to full effect by Margaritaville and another fashion tenant also heading to the property.

Margaritaville just branded a new hotel in Hollywood managed by the same group that manages the Savoy Hotel in Miami Beach, which is owned by Allied Partners — and sources said had been discussing this deal for some time.

Originally marketed by Richard Baxter, Ron Cohen, Jon Caplan and Scott Latham and Stephen Shapiro of JLL and contracted for $295 million, we hear B+B and partners will now pay around $300 million. Allied and Brickman paid $185.5 million in 2013.

The building is a mecca for songwriters and is the setting for HBO’s “Vinyl.” It sits along the corridor off the Bow Tie that could benefit from the “Nordstrom effect” when that department store opens a few blocks north.

Those reached declined comment as the deals are all pending closing.

In another retail switch, Tesla is once again negotiating for the ground floor spot at 860 Washington St., from which it can launch its local test drives onto the cobblestone streets.

For a while, it appeared Tesla was a shoo-in. Then Starbucks took the lead on Washington as it negotiated for a two-level flagship Roastery concept. But Starbuck’s baristas ultimately leased 20,000 square feet on the ground floor of the upcoming nearby 61 Ninth Ave.

Now, if Tesla ends up with the Washington Street ground, the developers will have another brand to help lease the rest of its retail space.

With everyone in retail in Las Vegas for RECon 2016, all parties reached declined comment.

Merrill Lynch will vacate its space at 717 Fifth Ave. to move to 75 Rockefeller Center in 2017.

Now, the Chinese owners of the office condo portion of 717 Fifth will stick with offices and have hired a Cushman & Wakefield team led by Fred Smith to lease the 138,000 square feet on the fifth through eighth floors. Asking rent is $95 per square foot.