Not sure if you noticed, on 14/May, we plan to start early from Sangla to Chitkul and back, and then head towards Nako for the night. Do you think this will be too stretched for a days drive?On 14th, finish sightseeing at Chitkul and then head to Kalpa for the night, unless you want to rest on this day.
Next day you can easily do Kalpa to Tabo, unless you really wish to spend a night at Nako.