Rashi on Deuteronomy 33:16/רש"י על דברים ל״ג:ט״ז

1ורצון שכני סנה — the last two words are the equivalent of שוכן סנה (the י being the suffix that that sometimes appears in participles, for the most part in poetry). The-meaning is: And may his land further be blessed through the favour (רצון) and satisfaction of the Holy One, blessed be He, who first revealed himself to me in the thorn-bush (סנה‎).

2רצון means satisfaction and appeasement, and similar is the meaning wherever רצון occurs in scripture.

3תבואתה LET IT COME — i.e. let this blessing come לראש יוסף ON JOSEPH'S HEAD.

4נזיר אחיו means THE ONE WHO WAS SEPARATED FROM HIS BRETHREN through his being sold.