Amateur nature photographer here.
I have a Canon 80D and the Tamron 150-600. It's a good start but you will eventually want a lens with a higher quality image and not so much the zoom capability. However depending on how tough you are going if you plan on doing nature photography, a zoom lens might be a better choice.
I do nature photography in the middle of the jungle and it's a better option for me to carry a single lens that has variable focal lenght than multiple lenses. The Tamron lens is quite heavy too, so you have to consider how much weight you are willing to carry around.