The hosts are winless in Group L and sit third heading into their fourth group game, whereas Nigeria currently lead the way with seven points accrued from a possible nine.
You would struggle to find a single soul who could have predicted that Nigeria and Sierra Leone would both hit the back of the net four times in their showdown on Friday, but that is exactly what happened at the Samuel Ogbemudia Stadium.
Nigeria looked on course to reach double figures in the game as Victor Osimhen, Samu Chukwueze and Alex Iwobi (2) put them 4-0 up inside the first 30 minutes, but Gernot Rohr's side simply capitulated as Sierra Leone's substitutes made all the difference in the second 45.
Kwame Quee reduced the deficit to 4-1 on the stroke of half time, with Mustapha Bundu and Alhaji Kamara (2) coming off the bench to complete an astonishing comeback and deny Nigeria the chance to extend their 100% start to qualification.
While the Super Eagles would undoubtedly have been shocked to the core by Sierra Leone's phenomenal turnaround, Nigeria remain top of Group L by one point ahead of second-placed Benin, although Rohr's side have now shipped the most goals in the group following that eight-goal thriller.
Top spot is exactly where Nigeria aim to be when the group stage reaches its conclusion in March 2021, and with Benin expected to overcome Lesotho this week, the Super Eagles can ill-afford to throw away another lead in such calamitous fashion when they face off against Sierra Leone again.
In contrast, this weekend's hosts managed to move off the bottom of the group at the end of matchday three, which is no less than their incredible turnaround warranted.
88 places separate Nigeria and Sierra Leone in the world rankings, but having notched up four goals against one of Africa's top teams, Sierra Leone are sure to be heading into this encounter on cloud nine as they bid to make an unexpected appearance in the AFCON tournament.
Four of Sierra Leone's five goals in the group were scored on Friday, with the Leone Stars opening their campaign with a 1-1 draw against Lesotho before suffering a narrow 1-0 defeat to Benin.
If anything has been learned by the other teams in Group L, it is that John Keister's men will never go down without a fight and have every reason to believe that they can defy the odds and finish in the top two.
Leone Stars have only appeared at the Africa Cup of Nations twice in 1994 and 1996, and it would take something remarkable for Sierra Leone to secure qualification for the 2022 tournament, but their never-say-die attitude was evident last week and Nigeria are sure to be nervous at the prospect of another showdown with Keister's men.
Sierra Leone AFCON form: DLD
Sierra Leone form (all competitions): LWDLLD
Nigeria competition form: WWD
Nigeria form (all competitions): WWWLDD
Sierra Leone's substitutes made quite the impact against the Super Eagles on Friday, with Bundu and Kamara both staking their claims for starting roles in this one.
Kamara now boasts five goals in six games for the national team - an impressive return indeed - and the 26-year-old could replace the veteran Kei Kamara here.
Wholesale changes are unlikely, but Queens Park Rangers defender Osman Kakay was brought off the bench last week and will be hopeful of featuring from the off on Tuesday.
As for Nigeria, 21-year-old goalkeeper Maduka Okoye was given the nod in between the sticks for Nigeria's first clash with Sierra Leone, but having shipped four goals on the night, the more experienced Daniel Akpeyi may be recalled for this one.
Another sombre sight for Nigeria was Osimhen being forced off on a stretcher in that pulsating draw, with Rohr since confirming that the Napoli man will miss out after he dislocated his shoulder.
Sierra Leone possible starting lineup:
M. Kamara; Kakay, Bangura, Sesay, Wright; Medo, J. Kamara; Bundu, Quee, Buya Turay; A. Kamara
Nigeria possible starting lineup:
Akpeyi; Akpoguma, Balogun, Troost-Ekong, Sanusi; Etebo, Aribo; Chukwueze, Iwobi, Ejuke; Iheanacho
We say: Sierra Leone 1-2 Nigeria
Sierra Leone and Nigeria would go down in the history books if they could somehow replicate or better their phenomenal draw here, but we are expecting a much more low-key affair on Tuesday. Leone know that they can hurt Nigeria going forward and the Super Eagles may be tempted to err on the side of caution in order to avoid another disaster-class in defence, but the visitors will be out for blood and we are backing Nigeria to scrape a hard-fought victory on matchday four.