Nasal polyps or a nasal tumor would be causing a lot of other symptoms. If you were experiencing any of those symptoms, or if a polyp was visible on exam, your ENT would be ordering additional tests.
My son gets nosebleeds constantly and to alleviate his fears, we once did an experiment where we dropped a few blops of red food coloring on a tissue so he could see how far it spread. One little drop made a 1/2-inch stain. So a tiny amount of blood can look like a scary amount during a nosebleed because of the capillary action of cloth or paper fibers causing the blood to spread. Maybe you are rubbing your nose at night without realizing it and that's why you're seeing blood in the morning? If it's just a tiny amount, I'm sure it's nothing to worry about. Best of luck.