The club-record £4million signing from Sunderland netted either side of a Jay Bothroyd effort as the Bluebirds ran riot with three goals inside 24 minutes in the opening period.
Chopra - back with the Welsh club after an unsuccessful two-year spell with the Black Cats - broke the deadlock after 21 minutes and bagged again on the stroke of half-time.
Bothroyd was also on target and Peter Whittingham converted a late penalty to ensure Scunthorpe endured a miserable return to English football's second tier.
But for two early David Marshall saves to deny Gary Hooper and Martyn Woolford it would have been Scunthorpe who edged ahead, before Chopra punished the visitors for their profligacy with his first goal since rejoining the Bluebirds from Sunderland on a permanent basis in the summer.
The former Newcastle striker linked-up well with Whittingham before drilling low past Joe Murphy from just outside the penlty area with 21 minutes gone.
Chopra was unfortunate not to find the net again two minutes later, striking the post from 18 yards with a right-footed effort.
The woodwork only offered a brief period of respite for Scunthorpe, though, as Bothroyd clinically doubled Cardiff's lead just after the half-hour mark from close range following Joe Ledley's left-wing cross.
Whittingham blazed a 30-yard free-kick wide before Chopra ensured the home side went in three goals to the good at the interval as he scored his second of the afternoon on the stroke of half-time.
This time it was Bothroyd who was the provider, allowing Chopra to rifle into the top corner of the net from 12 yards.
Paul Hayes tested Marshall after the restart from an acute angle, while at the other end Mark Hudson headed Ross McCormack's inswinging corner just wide.
The bustling Chopra continued to cause Scunthorpe no end of
problems as he went in search of his hat-trick as he drilled straight at Murphy from the edge of the penalty area on the hour.
Murphy was then required to pull off an impressive point-blank save to keep out Chopra's close-range effort from another McCormack corner, with Hudson powering the resulting rebound over.
Whittingham again went close from the edge of the penalty area as Cardiff continued to surge forward in impressive fashion and Bothroyd saw a weak headed effort blocked by Murphy.
With 10 minutes remaining, Grant McCann cleared an inswinging Whittingham corner off the line before Josh Wright tried his luck from 30 yards during a rare Scunthorpe attack.
McCormack went close late on before Whittingham completed the scoring in added time from the penalty spot after Ian Morris had fouled Chris Burke.