What lens for D810

Hi all i have just bought a Nikon D810 and although iam a Canon shooter the deal i got on the Nikon was to good to pass on.
I mainly shoot nature and landscapes so iam looking for the best general purpose wide to medium lens for the 810.

Thanks in advance.

Jingler

Perhaps start with a 24-120 f/4 lens or give the Nikon f/1.8 primes a look.

Zoom:
Absolute best Nikkor = 24-70Vr
The old 28-70 is still a very well regarded lens and the recently superseded 24-70/2.8 is just as sharp as the VR in the centre - the VR kills its older stable mates away from the centre though
The 24-120 f/4 VR (not the older variable aperture lens) is also a fairly good option from what I've read.
Sigma 24-35 is another very, very good option though limited in range to between very wide to just wide
Sigma's 24-105 is another option but I'm not sure it's noticeably better than the 24-120/4

Ultrawide Zoom: 14-24
Nikon's 16-35 and 17-35 are both pretty good, just not quite in the same league IMO
Their new 18-35 variable aperture lens is also pretty good from what I've seen too

Very wide to wide prime:
Any of the Sigma Arts such as the 20, 24, 35, 24-35 (IMO better than the Nikon 1.8G primes in this focal range)
You've also got Nikon's 24 and 35mm 1.4G primes and Nikon's 24mm PCE (though some might argue it's not as good as Canon's 24 TSE II)

If you want a cheap alternative but as good enough then go with those:

Tamron 15-30
Tamron 24-70
Tamron 70-200

Forget temporarily about Nikon lenses and start with these until you find you want to stay with Manufacturer lenses when you can afford them.

Used 24-70mm G, or new Tamron 24-70mm VC; I only suggest new when buying Tamron because sometimes you need to exchange it a couple times until you get a good copy of their lenses, plus they have that 6yr warranty.

ETA: if by nature you mean animals/birds then depending on how much reach you need: I'd also go for either a used Nikon 80-200mm or 70-200mm, or Tamron 70-200mm VC....or from what I've seen (never used personally) the new 200-500mm is capable of some really nice shots too. A "do it all" lens that goes from wide to moderate telephoto probably isn't going to be the best choice, especially considering the body you have (ie. going to show all the shortcomings of lenses).