Vietnam exports rice to Nigeria. Nigeria exports cashew nuts to Vietnam.

Nigeria wants to shut its market to imported Vietnamese rice - and believes that Vietnam cannot retaliate by buying less Nigerian cashew nuts and focusing on other suppliers like Guinea Bissau & Benin.

Cashew nut exports from Nigeria dropped from around N61 billion in 2018 to around N39 billion in 2019 (NBS stats, not mine).

I can't see how gridlock at Apapa, plus border closure will facilitate exports.

Me, I no sabi book like @EurasiaGroup, just my uninformed musings.