Can anyone provide information for the uniform in this watercolor? It was discovered in an estate sale in New York City as part of a larger art collection (no other similar pieces). The lettering at the bottom reads "la mascotte du Régiment Nisse" (not sure of the exact spelling of the last word as the script is faded). Any help would be greatly appreciated. Thank you.
It looks like a WWI Russian uniform. "Nisse" is probably "russe".
The sketched uniform is rather devoid of identification marks except for the cap. Look at Brusilov's field uniform for comparison (from Wikipedia):
Yeah the buttons don't match those (not) sketched.
But there was a lot variation; see the photo collection of Visser for instance
The OP didn't provide any details where that might have been sketched, but there was Russian expeditionary corps sent to France. The photo below is from when they disembarked in Marseille in 1916.