It's a log of Nike reduced to a checkmark. The checkmark had a black outline and is white in the middle, pretty much looks like the logo on all of Nike's clothing.
This is the Nike icon for Windows 10
. Here we go. Optimized for 32x32 px, these are the simplest icons in the line style. Downloadable formats are PNG and SVG, among others. Icons8 icon pack is unique in providing a huge number of icons designed by the same team of four designers who create the new icons every working day in the same style and with the same quality. Same cool as the Bat Face, huh.