Playing before former players on Alumni Day, the Senators controlled the lead throughout the game, but every time it looked as though they would turn the game into a rout the visitors would battle back within striking distance.
However, the lead finally got big enough that even a 14-2 run over a span of just over three minutes couldn't get the Pioneers close enough at the end.
Powell poured in 27 points, Boyd added 20 and Machado scored 19 and grabbed 15 rebounds as the Senators improved to 15-11 for the season. They are now 8-7 in Tennessee Community College Athletic Association action.
Powell scored 21 and Boyd 17 in the second half, while Machado had 16 before intermission when the Senators led 45-48.
Zach Morris topped the Pioneers balanced attack with 20. Justin Goodson added 18, Austin Fisher 15 and Brian Price 13.
Volunteer State fell to 3-17 and is still winless after 14 conference games.
Walters State coach Bill Carlyle was disappointed in his team's inability to put the game away. "We did some really good things and looked great for a while and then we turned around and let somebody get back in the game.
"We're just too selfish as a team," he explained. "We don't play as a team at times, we play as ourselves. Until we learn how to take care of the basketball and do the things we're supposed to do it's going to keep happening."
Carlyle continued, "We had huge leads two or three times and couldn't hold it because we're selfish. But we've been working on the same things all year and it looks like it's not going to change."
The Senators hit a hot 53.9 percent from the floor, making good on 41 of 76 attempts. Carlyle's club hit 8 of 21 from behind the arc. Volunteer State hit 32-69 for 46.4 and was good on 15 of 38 three-point attempts.
With Machado leading the way, Walters State controlled the backboards, 47-28. George Robertson led the losers with eight.
The game was tied only once and that was at 2-2. Powell hit a basket and Sly Thompson gunned in a trey and the Senators led the rest of the way.
It was 25-20 when Machado hit two baskets and Jamiah Holloway, Powell and Izayel Pierre all added one in a 10-1 run that stretched the lead to 14-1.
But, the Pioneers rallied within seven at the break by making three triples in the final three minutes of the half.
A dunk by Morris pulled Volunteer State within five to start the second half but the Senators reeled off 10 straight points and appeared ready to break it open again as another six-point run made it 63-45.
However, the visitors responded again with a 10-2 spurt capped by threes by Price and Goodson to close within 65-55. It was the Senators' turn to spurt and they ran off 10 straight to lead by 20.
Powell hit back-to-back treys and Boyd had a dunk and layup for the biggest lead of the game at 91-67 with 6:19 to play. A three by Price got the lead all the way down to 11 at 95-84 with 1:49 remaining, but Powell hit a basket, Thompson added two charity tosses and Jordan Wilkerson fired in a three form the corner.
The Senators hit the road to take on TCCAA rival Southwest Tennessee Saturday at 5 p.m.