The DC Court of Appeals has ruled that the Cherokee Nation cannot be sued without its consent. However, the decision leaves open the possibility that individual tribal officials can be sued for violating the 1866 Treaty. Discussion of the issue at John Cornsilk's Place. Links to the briefs at Turtle Talk.
Based on a very limited analysis of the decision, it seems to me that if the trial court (which, remember, ruled that CN had waived sovereign immunity) allows suit against the Principal Chief and the Tribal Council individually, then not much will have changed, though I'm curious as to what the Freedmen's remedy would be if they prevail under those conditions.
UPDATE: More on the story from Indian Country Today.