Friday's victory in Kingston clinched the three-match series 2-0, with the final game to be played on Sunday at the same venue and to be followed by three ODIs.
After reaching his fifth T20 half-century, Phillips went on to make 76 from 40 balls and led New Zealand to 5-215, exceeding the 5-185 which was enough to win the first match of the series.
His innings included six sixes and four fours.
The West Indies managed just 9-125, never threatening New Zealand's total which was the highest by a visiting team against the West Indies in a T20 in the Caribbean.
Phillips put on 71 for the third wicket with Devon Conway who made 42 from 34 balls and 83 with Daryl Mitchell, who made 48 from 20.
Phillips put to good use his knowledge of conditions at Sabina Park, which is his home ground in the Caribbean Premier League.
"Coming back to Sabina Park is amazing. I've got great memories here," he said in a television interview. "Being able to get a 50 for my country over here in front of a crowd which I really love is definitely very special for me."
Seven West Indies wickets fell to spinners, including the first four of the innings.
"We just didn't show up today," Windies skipper Nicholas Pooran said. "They batted us out of it and we couldn't see our way with the bat.
"We had to stay in the game. It just didn't start well for us. We are struggling but the more cricket we play our performance will grow."
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