Nienaber said, on a South Africa Rugby podcast, "If you look at the achievables that we probably set out before the year started, the British & Irish Lions was a big focus for us.
"Then defending the Rugby Championship was one of the things we set for ourselves.
"Then, I don't know when last we had an end-of-year tour where we didn't lose a match, so that was an objective. And the fourth objective was to see if we can finish the year at No1 in the world again, having started the year at No1," he said.
They ended up having achieved about half of their goals,
Nienaber said the Springboks had been up and down in the Rugby Championship and had narrowly lost out during their November tour.
Despite that, they had still ended No1 in the world.
"So, I would probably say, between a five and a six out of 10," he said.
Nienaber said he couldn't wait for the Springboks' first Test of the year against Wales in July.
He intends to name his first squad at the end of May.
"There is nothing better than starting your season with three proper Test matches against Wales. I think the fans are also excited," he said.
"We haven't had the Rugby Championship here since 2019. The last match against the All Blacks [in South Africa] was in Pretoria [in 2018].
"It's a nice, and tough, schedule, but I think that's what you want a year before the World Cup. You want to play big opponents, and if you look at the eight nations we are playing, and the world rankings, we are playing Nos two, three, four and five.
"And the other four opponents that we are going to face this year, only one of them are outside the top 10," he said.
At the same time, Nienaber has been under pressure to grow depth in his squad and give emerging players a chance.
He said they were trying to create a chance for new players.
"Reviewing the squad we had last year, and where is their opportunity for change – looking at experience, looking at age, looking at bringing some new players in – from a player point of view there is a blank canvas. We are looking for players that will knock the door down," he said.