All winter tires are only good for the first half of the tread life. The Blizzaks have 2 wear bars, one to indicate end of winter service and one for ultimate service life. Not only is the sticky winter rubber compound gone at half tread life, but half the sipes. Due to the large number of sipes, only half the sipes are full depth. The large number of sipes cause the tires to squirm and cause vagueness and some wandering (very evident on grooved concrete highways). If all the sipes were full depth it would cause handling issues. On studded tires, at half tread life/depth the majority of the carbide tips of the studs have worn/broken off. At this point the aluminum stud bases do nothing for traction but rattle around. I have run close to 10 sets of blizzaks. IMO they are the gold standard for a winter tire. Blizzaks are performance tires and as such wear like performance tires.
Your XSE came with 235/55r19, 101 rated tires so a 102 should be fine. A high load rating is stiffer and generally rides rougher. Blizzak also makes a DM-V2 which is more suited for heavier vehicles. I have driven both the WS and DM tires on our RAV. THe WS has a little more ice bite to them probably because they are softer. I feel like any of the modern studless winter tires all do about the same. Test might show that one might have a few less feet in stopping distance or a few tenths faster in acceleration, but in the real world is hardly matters. For my wife's new car I bought some Micheline Ice X-SUVs this year. Haven't run them yet, but I expect them to be jsut as good as the blizzaks. They do claim full thread depth winter compound. But their winter rubber is a silica based rather than the multi cell (water absorbing/displacing 'foam') of the blizzaks which make them more durable. Not sure they will do much better at half thread; we'll see.
As far as the Nokians go. They no longer list the Nordman on their website. THe only places that carry them are some of the odd ball on-line tire vendors like Walmart and simple tire. I am guessing these are discontinued tires which might mean they are getting up there in age; if that matters to you. THe big question is, do you want studded? DO your local laws allow for them? Guess yes as your daughter runs them. Will the clickity clackity of the studs drive you mad? Though stud patterns on newer tires are much better than the old 2 outside row only placements, I don't think I will go back to studs. Ice rink test use to show studless doing better, but with the newer full face studding patterns the studs are showing a slight performance benefit on ice.
