Hello Jacqui,
i'm 24 months into Nilotinib now and have read mixed reports about the fasting element. I tend to stick only to water - however, i have been known to have a cup of weak black tea 30 mins after taking the meds. The risk you are mitigating by fasting is the QT prolongation. This was found in a small number of patients during the trial. A suspected cause is taking Nilotinib with food which increases the efficacy of the medication.
So bearing in mind the small number of people who would actually be affected by this and the fact that you're drinking tea, not a protein milkshake or 3 course dinner, then your risk of an adverse reaction is probably quite low. But this is your decision and my own view is each time I deviate slightly from the defined schedule or rules, I am leaving myself open to an increased risk of some description - that's not to say i don't deviate i just have periods of minor guilt :-)
I feel pretty comfortable having a weak cup of tea as described within the fasting periods - whatever you're comfortable with.
Out of interest did your doc do a baseline ECG prior to you starting Nilotinib?
Hope that helps
Chris