Diabetes: nutritionist says protein helps "cancel" out carbs and to try to eat things that have it IE: 19g carbs 14g protein. How does it work?

Protein vs carbs. Protein doesn't cancel out carbohydrate. I think the nutritionist was simplifying it. Protein and fat will keep your blood sugar more stable for longer periods of time. Eating a high carbohydrate diet will cause blood sugar surges and then hypoglycemia. That will cause you to become hungry and eat again. This creates a cycle of high/low blood sugar and may make you tired and anxious.
Protein & glucose. Shortly after a meal of pure protein, the glucose level drops and then may go up a few hours later as the liver starts converting amino acids from the protein into glucose. This pattern is the opposite of what happens after a meal of pure carbs, where the glucose level shoots up, and then may drop low a few hours later. Eating a meal with carbs and proteins helps stablize the glucose levels.