Macro Lens with Nikon D60?

I'm interested in pursuing a career in nature photography.
I used tamron tele macro 70-300 mm lens to get to learn basics.
since i'm comfortable handling it, I would like to take your
suggestions on the next level of lens for macro photography
preferably [105mm f2.8 range]

i'm confused between nikor lens (which are way too expensive,
but seems too good to resist) and sigma/tamron…

would love to hear your experiences handling these lenses,
based on which i will take my decision.

~ Sunny

Added (1). I read about the nikor VR 105mm f2.8, how different is it from the old ones…

When buying a lens it should be thought of as an investment since with reasonable care a quality lens will outlast you.

The two major differences between the older Nikkor AF 105mm micro lens and the newer Nikkor AF-S VR 105mm micro lens is the fact that the AF-S version will auto focus on your D60 and has Nikon's Vibration Reduction (VR) technology. Another difference is that the older AF model requires the PN-11 adapter to achieve a full 1:1 reproduction ratio and the newer model doesn't. If you're comfortable with manually focusing and plan on doing a lot of your macro work with your camera on a tripod then the older version should be fine.

On the other hand, if you plan on using the 105mm micro as a short telephoto hand-held then the newer AF-S VR version might be a good choice.

Not a lot of call for macro nature photography careers… Most nature photographers go for the "bigger picture"…

i use a tamron 90mm f/2.8 macro lens… With extension tubes…