Make one, or apply one? If apply, under Create Maya Nodes, open the Evn Nodes, pick the kind you want, throw in your reflection map file into it, then link the env node with the reflection color value on your main shader.
Unless you're using a shader other than one provided with Maya, then yes. All you have to do is connect the image you're using for the reflection to one of the Env. Nodes, then connect it to the reflection color slot (make sure to set how reflective you want it to be using reflectivity or another file).