F.L.U.D.D. *do not use*
Absolutely no good reason to use Nayru's love against this projectile... it does essentially nothing.... just punish him with some other move... nothing more to say here
Link's Arrow - *recomended*
Unless he's uber far away, he won't be able to protect himself from a reflected arrow... and if he IS that far away, he can't rush in to punish you for it... so reflecting it is completely safe and normally results in some free damage against link... it's not exceptionally stong, but, hey, damage is damage right?
Chef *personal preference*
umm... sure. I mean... odds are very slim that the reflected food will actrually make it BACK to game and watch, but if you want to short hop a nayru's INTO game and watch... it'll protect you from his food while you do it.
Icicle *personal preference*
much like link's arrow, free damage is fre damage right? Assuming you can reflect BOTH icicles and not one into the other to cancel them out... and also assuming the icies aren't close enough to grab you afterwards, yesh I suppose this could work... but normally I'll just eat the ice floes and trade with a din's
Final Cutter *not recommended*
The shockwave from final cutter? really I suppose you COULD reflect this... it's just... what kirby ACTUALLY tries to use this as a projectile?
Luigi's Fireball *recomended.... or personal preference*
once again... you have the option to reflect or to countercamp with Din's.... chose whichever option fits the current situation better... just be sure that luigi can't punish your nayru's lag.... but, most of the time, he won't... so Nayru's works well... I'd recomend reflecting if he's close... otherwise the fireball probably doesn;t have much of a chance of hitting him.
PK Fire *recomended.... BIG time*
honestly ask Raph.... the fact that I can reflect PK fire REALLY puts a kink in Ness's plans... it severely limits his follow up options even if he DOES connect with zelda.
Pikachu's Thunderjolt *recomended*
at the very least it'll discourage a camping pikachu... and it's hard if even possible for him to punish your cooldown lag from it... The damage it does if reflected (if it connects... which it probably won't) isn't great, so you might consider countercamping with Din's... but NL is a very solid and very safe option.
Olimar's Pikmin Throw *recomended*
assuming thatolimar is close enough that the reflected pikmin will latch on, then hellz yeah... it's free damage against him! if he's too far away... use din's... simple as that. not much more to say there.