Murray got to know Nienaber when he was an assistant coach to Rassie Erasmus - the current Springboks director of rugby - at the Irish province for the 2016/17 season.
Nienaber and Erasmus have since combined to win the 2019 Rugby World Cup and will be bidding to dent Ireland's aspirations to take their crown from them in the keenly awaited Pool B match in Paris next Saturday.
Both sides come into the match on the back of two wins from their two games.
"There is familiarity with having been coached by Jacques (Nienaber) and all the lads," said Murray following the 59-16 win over Tonga.
"But they are the type of guys who come up with new plans and tricky little things in new games, so you have to be prepared for everything.”
Murray, who started against Tonga but is likely to be on the bench with Jamison Gibson-Park coming back into the side, said the Irish may have scored 20 tries in their opening two matches but the Springboks pride themselves on their defence.
He said South Africa had signalled their intent in terms of defence in their record 35-7 defeat of New Zealand in a warm-up match at Twickenham last month.
"They are a difficult outfit to play against, on both sides of the ball," said the 34-year-old.
"In terms of their defence, you have seen their defence, especially in Twickenham, so we need to try to navigate around that.”
'Why are you here?'
Murray, whose father Gerry watched his son play on Saturday only months after he suffered life-threatening head injuries when he was knocked off his bike, has been an essential part of many great matches and moments with Ireland since he made his debut in 2011.
Two Six Nations Grand Slams and a historic series win in New Zealand last year number among them but Murray still professes to being nervous.
"You'll be buzzing," he said. "With nerves, of course. The usual stuff. You'd be afraid if they weren't there.”
However, even such a seasoned campaigner is champing at the bit to face the Springboks, which surprisingly will be a first for both sides in World Cup history.
He will be hoping for as memorable an experience as when he won his 100th cap last year against the same opponents in Dublin, the Irish winning 19-16.
"Playing the world champs in Paris, if that doesn't get you excited, or even like tonight (after the Tonga match), when you're listening to that atmosphere, one of the lads said it: 'If you can't enjoy this, then why are you here?’
"So, you have to embrace it too and enjoy the challenge. It's going to be a massive challenge, world champions in a World Cup.
"It's something really exciting."