Is it alright to leave my 2015 Rogue in the ECO mode 100% of the time?

I would refer to the owner's manual on this issue. I am pretty sure it would be fine, but I am NOT positive.

Its fine we run ours in that mode , it helps the gas miles so far. Seem to have less power to get up and go in that mode.

I've had 3 rogues and have run all of them in eco mode most of the time with no issues,,2 things to consider: 1) nissan recommends turning off the eco mode when using the air conditioning 2) I have found that not turning on eco mode in the winter, (very cold outside ambient temp), until the car warms up is better..otherwise, it will stay in low gear too long until it warms up 3) wouldnt worry too much about "less" acceleration in eco mode..these arent hot rods anyway, acceleration is acceptable in eco mode and your optimizing fuel economy..if you desire more pick up/acceleration, get a murano