"My first run wasn't as good as the last one".
Marcus Kleveland earned the coveted win with his first run.
Fellow Estonian and Cincinnati Bengals defensive end, Margus Hunt even showed his support for his fellow countrywoman on Twitter as he watched from home.
Sildaru, whose birthday is February 17, is the second woman to win two medals this week, joining snowboarder Julia Marino (gold in slope, bronze in big air).
"This means the world to me, I've been watching the X Games for years and this means everything to me", said Nicholson following the event.
Next February, on Day 9 of the 2018 PyeongChang Olympic Games, Sildaru will celebrate her 16 birthday, and if the X Games are any indication, the party should be super sweet.
Great Britain's James Woods claimed gold in the men's ski big air at the X Games in Aspen, Colorado. Norway's Johanne Killi, 19, repeated as the bronze medalist with a final 85.66-point run, knocking off 18-year-old Giulia Tunno of Switzerland, who won bronze Saturday in big air.
Nicholson's team-mate Mark McMorris, Olympic slopestyle bronze medallist at Sochi 2014, finished third after his routine was given a score of 87.33. McMorris's other run was a 48-pointer.
The 14-year-old, who claimed slopestyle gold last year, topped the podium with a formidable score of 92.33 points, achieved during her first run.
On Friday, Max Parrot of Bromont, Que., successfully defended his Big Air title while landing the first-ever quad underflip in competition.