Charlton Mashumba, Brice Aka, Pentjie Zulu and Sipho Mngomezulu netted for Ezenkosi, while Rhulani Manzini, Aristide Bance and William Twala were on target for the Chilli Boys.
Cosmos bolstered their tally to 10 points from 11 games, but remain 14th on the Absa Premiership table - five points above the drop zone.
Chippa are eighth in the standings with 13 points from 11 matches.
Zimbabwean hitman Mashumba opened the scoring in the 20th minute as he rifled the ball through the legs of goalkeeper Daniel Akpeyi.
Mashumba's strike partner Aka doubled the advantage from the spot in the 27th minute after Sandile Zuke was adjudged to have handled in the box.
Zulu made it 3-0 to the hosts soon after with a clinical volley on the angle in the area.
The Chilli Boys pulled one back in the 37th minute through substitute Manzini, who netted from close range shortly after replacing Andile Mbenyane.
However, Mngomezulu added a fourth goal for Cosmos just before the break by steering in a right-wing cross in emphatic fashion.
The visitors reduced the deficit in the 71st minute, as in-form striker Bance beat Sherwyn Naicker at his near post with a low finish.
Twala ensured a tense finale as he sneaked a shot past Naicker with four minutes to go.
Sono's charges, however, held on to collect the three points.