I am 22, and my mom is 59. So, my mom got diagnosed with breast cancer back in 2005, and took radiation and chemotherapy in late 2005/2006. Anyway, she's doing well now except for red-green color blindness and she has nausea pretty much every morning. She, of course, takes nausea pills (Promethazine) and drinks Ginger Tea. Yes, the ginger tea helps it go away, but then it comes back the next morning persistently. I just don't know a way to prevent it from happening in the first place? Is there any thing I should be looking into to help? Any remedies or anything that helped anyone in a similar situation?
Yes, you should be looking into getting help.
Nausea during chemotherapy is very common, and should be treated. But nausea in the morning 9 years after chemotherapy? That is not at all normal.
There are a great many medical problems that can cause nausea, including, unfortunately, a possible recurrence of her cancer. These should be ruled out by her doctor(s) as soon as possible.
While you are waiting to see the doctor, you mentioned, ginger is a natural anti-emetic (anti-nausea). Ginger tea, ginger ale and even candied ginger can help. Eating 5-6 smaller meals, rather than 3 large meals, helps, as does keeping plain crackers by the bedside and eating some as soon as she wakes up (before rising), and rice or toast at night.