Twentyfive of the 39 debutants -- 64.10 percent -- headed home after first rounds comprising two or three group matches.
Burundi, Madagascar, and Mauritania in Group E, could suffer similar fates this month as they experience a higher level of competition for the first time.
German Rohr, whose Nigeria team are among the favourites to win the June 21-July 19 tournament in Egypt, stressed that no opponents should be treated lightly.
"There will be no easy matches for Nigeria," stressed the 65-year-old ahead of their opening match against Burundi in Mediterranean city Alexandria this Saturday.
Using the latest FIFA world rankings as a guide, the Nigerian Super Eagles should win comfortably as they are 89 places higher than the Burundian Swallows.
Informed of the gap, Rohr said "my team will never underestimate any opponent no matter what the rankings suggest".
Rohr added that Burundi had qualified instead of Pierre-Emerick Aubameyang-led Gabon and that should serve as a warning to his team.
Guinea complete Group B and Belgium-born coach Paul Put echoed the views of Rohr that the two newcomers they will face deserve respect.
"Who is to say debutants cannot progress beyond the first round," he said. "Guinea and Nigeria have to be extremely careful in the group.
"Countries making Cup of Nations debuts are usually dismissed as outsiders by the media, which takes all the pressure off them and makes them even more determined to cause shocks.
"These so-called weaker sides have nothing to lose and everything to gain. Our concentration levels from the kick-off to the final whistle have to be 100 percent."
While Rohr and Put preach caution, the reality is that since newcomers/hosts Libya came second in 1982, 13 of the 16 debutants were eliminated after the first round.
The last team to progress beyond the first round were Cape Verde, who qualified for the 2013 quarter-finals at the expense of Angola and Morocco before losing to Ghana.
In the modern era, South Africa are the only newcomers to become champions with home advantage, 80,000 crowds and 1,753 metre (5,751 feet) altitude factors in the success.
The 2019 tournament kicks off Friday at the Cairo International Stadium with a Group A match between Mohamed Salah-inspired Egypt and Zimbabwe.