It’s not so much the extra travel that you will notice on the climb but rather the extra weight. I think the general consensus has settled down to 140mm or thereabouts is the optimum for UK trail riding. 150mm is only 10mm more but there are 150mm travel bike and then there are 150mm travel bikes, i.e. the modern crop of 150mm bikes were previously 140mm bikes and were built to a target weight of around 27-28lbs. There was a previous crop of 150mm bikes, best empitomised by the 2005 SPeclialized Enduro, that were coming in more like 32lbs.
My point is this.
It’s not so much about how much travel the bike has, it’s more about how it uses it and how much it weighs. The orange Five is a case in point, light, effecient, fast etc. With a good damper, set up well, it will pedal as well as a bike with 120mm of travel, but it will be a little heavier.
If you’re not too worried about carrying a few extra pounds then the Nerve AM will be able to evolve with your riding more readily than the Nerve XC.