Is it advisable for a diabetic to take nitric oxide?

No reason. Nitrix oxide has not been approved for the treatment of diabetes as of now. Its off label use varies greatly, but I would not prescribe or recommend it for routine use without a clear evidence of efficacy.
NO. People can not "take" nitric oxide. It is a gas made inside your body naturally. Diabetics should review their diet, physical activity, medications and blood sugar levels with their doctor, nutritionist, or care provider to ensure their health can be optimized.