'twas not the kaypoonie....
the carrots ratted the dish out - seriously big time over-cooked.
wrinkled carrots be not a good thang . . . 
I've developed a different strategy for these kind of dishes.
first, the breast is too thick.  by the time anything in the middle is 'done right' the outer bits are dry&crumbly.
solution:  
1 - slice the breast in half thickness wise
2 - saute the (thinner) chicken bits to perfection done
3 - remove/reserve the chicken bits
then
4 - use the pan 'stuff' to cook the vegetables to tender - keeping in mind that not every vegetable cooks to "yum-yum" in the same time.  potatoes take longer than carrots&celery, beans/corn/(not dried) peas take way lots less time.  start the long cooking stuff, use a timer, add the quicker cooking stuff as you go along.....
5 - add the chicken/meat back to the pot - basically to re-heat - about ten minutes prior to "all done"
bottom line:  cook all things to "really good done" 
then put it all together to heat thru.
simple concept; some practice required.