going to be tricky for several reasons working together to make it unlikely
Orthodox nations didn't have the same ability to project themselves across oceans due to relatively few good harbours in waters with good access to larger Oceans (Norvograd might be the best one of those and they would have to push through the Danish and later Swedish superiority in the Baltics)
Orthodox nations would have to move around the Catholic/Protestant nations to get out into Atlantic Ocean, taking the most likely route (otherwise they'd have to push either to the Pacific or through the arabic states in Middle east to the Indian Ocean)
Most of the Orthodox nations focus were on defending themselves from attacks from land (Mongols or Ottomans cover all of eastern Europe), so they don't have the safety to retune their focus toward the new lands in the west.
Moscow pushing east earlier, and getting a strong infrastructure between their western and eastern parts (earlier railroads seem the only plausible one here) making a much stronger appearence in the northwestern Pacific Ocean, might well be the only possible way, if only having a PoD after the discovery, sure Courland had a few colonies (which failed), but they had the ability to focus (they were largely a naval based country, which leaned on Hansa and had a relatively big coastal area) and they were Protestant so they didn't have to jump the same loops that a Orthodox baltic nation would have to, to get out of the Baltic bathtub