We have to focus on the Bible definition of the term ‘god’.
So, what is ‘god’ according the Scriptures? Paul wrote that ‘god’ (θεος) was equivalent to σεβασμα (2 Tes 2:4), that is ‘an object of veneration, or, worship’.
Really, given a worshipper, or some of them, anything in the universe of the entia is able to become a ‘god’. According the Bible,  a human person (Rev 19:10);  one or some of the animals (Eze 8:10-11);  a part of our body (Philippians 3:19), or any other ens, animated or inanimated, is able to become a 'god', or an 'idol' for us.
When Paul said that ‘the idol is nothing’ (1 Cor 8:4) we do not understand it like an absolute acceptation of ‘nothing’, but a comparative one. In fact, in the same Paul’s letter (1:28) he spoke about, for an example, “the things that are not” (τα μη οντα) that, very clearly, they were (and are) existing things (as the first part of the verse says). Those “things” “are not” in a comparative sense, in fact the parallelism fixes the equivalence between the ‘things’ that ‘are not’ and the ‘things ignoble’ (αγενη). This aspect (comparative vs absolute acceptation) must be took in consideration also in 1 Cor 8:4.
In other words, compared to IEUE, the Creator, any of these ‘idols’, or ‘gods’ are like ‘nothing’. Since they cannot put an obstacle before His plans, nor, they can help their worshippers, in a comparative sense they are ‘nothing’.
This is a sound conclusion also if we take into consideration the often-expressed God’s quality of ‘jelousy’ (Exo 34:14, and many other passages). In fact, if the gods/idols were nothing in an absolute way, it is senseless – from God’s part – to demand his people not to serve ‘other gods/idols’. I think you do not ever read in the Bible that the Israelites answered God in the following way: ‘Excuse us, Lord IEUE, why you are concerned about to whom we are directing our worship? Since the ‘gods/idols’ you speak on are non-existing entia, at all, is there a basis for your ‘jealousy’?'
Truly, if I and my wife found ourselves on a solitary little island, with no people on it, at all, it wouldn’t be stupid – for my part – feel jealous of her?
From the moment God allowed us to receive the gift of free will, everyone of us is able to decide who or what to worship. This is why God is jealous, because he is the Creator, and to him deserves rightly our worship, honor, and respect (Rev 4:11), in an exclusive way.
This conception of God, the Creator, that provides that He deserves an exclusive worship, along with the acknowledgement of the existence of other σεβασμα (‘an object of veneration, or, worship’) is called monolatry. It is different from monotheism. Despite the vast majority of people is persuaded that Bible teaches monotheism, in reality we found that the Bible teaches, instead, monolatry. For users’ sake understanding let me present a simple analogy to illustrate the point of difference between these two important concepts.
A (so to speak) ‘monotheistic’ U.S. newspaper reader would be who believe that exists only one printed newspaper in his country, and reads it. He not believe that, as a matter of fact, there are – in U.S.A. – hundreds (or, thousands?) of different printed newspaper, every day.
Differently, a (so to speak) ‘monolatric’ U.S. newspaper reader would be who knows, for a fact, that in U.S.A. exist hundreds (or, thousands?) of different printed newspaper, every day, but, in every case, he chooses to read only one newspaper among them all.
So, if we understand these basic concepts and apply them on the passage at issue (1 Cor 8:4-6) we will not spot any discrepance, at all.