In addition to turning it off completely, you can leave it on but tweak the LKAS behavior between three modes: Lane Departure, Standard LKA and Active LKA. See page 6-81 of the 2018 USA Niro Owner's Manual (or probably some other page for other countries/editions). I tried Active LKA and got frustrated with it. I'm currently using Standard LKA which I think is the default: occasionally it tries to steer in a different direction than I want to go in, but the sensation on the steering wheel is similar to that of going over a small bump in the road: it's not a big deal. Active LKA is kind of the same, only more frequent and perhaps it's also a tad more forceful. I haven't tried Lane Departure, but I suspect that is just the alarm sounds without any active steering. I might eventually wind up with that setting, not sure.
About 0.1% of the time, the Standard LKA signals via the steering wheel in a way that I consider helpful, meaning that it points out that I'm a little too close to the adjacent lane and I should correct my steering, and I agree with that. About 2 or 3 % of the time, the Standard LKA sends mild signals via the steering wheel that suggest that it wants to go in a different direction than I do, and I frequently don't agree with those "suggestions".
When driving in heavy traffic, I sometimes find that I need to turn on the left turn signal to indicate to the driver behind me that I, just like the 10 cars behind me, plan to pass the traffic ahead that is going somewhat slower than everyone else. If I put on the turn signal while there's another car in the left lane, the Niro sounds a few chirp alarms for that. It's kind of annoying when I know there's a car to my left, but beneficial when I don't, and no one has yet figured out how to empower a car to know what its driver knows, so hard to fault Kia for this.
2018 Niro PHEV Gravity Blue