Yes, it can be done. The standard position is to force the enemy king into a corner of the same color as the bishop. Then there are four squares (the corner, the diagonal, and two lateral) squares that need to be attacked.
The bishop attacks the corner and diagonal squares, the king guards one of the lateral squares, and the knight the other one.
[FEN "8/5N2/8/5K2/8/5Bk1/8/8 w - - 0 1"]
[White "K + B + N vs K"]
[Black "White to play and win"]
[Result "1-0"]
1. Ne5 Kh3 2. Kf4 Kh4 3. Ng6+ Kh3 4. Bd5 Kh2 5. Kf3 Kg1 6. Ke2 Kh2
7. Kf2 Kh3 8. Be6+ Kh2 9. Bg4 {A waiting move to transfer a move to Black, so that the knight will arrive at its destination while giving check.} Kh1 10. Nh4 {The knight starts its journey to f1.} Kh2 11. Nf3+ Kh1 12. Nd2 Kh2
13. Nf1+ {The all-important destination-check.} Kh1 14. Bf3# {Note: White's bishop can be anywhere on the c8-h3 diagonal (except h3) before this move, and anywhere on the long diagonal to give mate.} 1-0
