Nonsense. The various Native American nations (held to be such by the US Supreme Court) signed some 29 treaties with the Confederacy. Lincoln's blockade of Southern ports was official recognition of the CSA as a belligerent power under International law, a fact noted by Thaddeus Stevens 9 Dec 1862:
'We, ourselves, by what I consider a most unfortunate act, not well considered -- declared a blockade of their [the Confederate States] ports -- have acknowledged them as a power. We can not blockade our own ports. It is an absurdity. We blockade an enemy's ports. The very fact of declaring this blockade, recognized them a beligerent power entitled to all the privileges and subject to the rules of war, according to the law of nations.'
Which countries, aside from the U.S., recognized the Indian tribes as sovereign nations?