It is most likely a gross misunderstanding of John 10:34, wherein Jesus references Psalm 82, which says in part "I have said, Ye are Gods".
Of course, as always if we look at it in its wider context, it doesn't support Mormonism at all, and actually makes quite the opposite point than the one Mormons want it to make.
22 Now it was the Feast of Dedication in Jerusalem, and it was winter. 23 And Jesus walked in the temple, in Solomon's porch. 24 Then the Jews surrounded Him and said to Him, "How long do You keep us in doubt? If You are the Christ, tell us plainly." 25 Jesus answered them, "I told you, and you do not believe. The works that I do in My Father's name, they bear witness of Me. 26 But you do not believe, because you are not of My sheep, as I said to you. 27 My sheep hear My voice, and I know them, and they follow Me. 28 And I give them eternal life, and they shall never perish; neither shall anyone snatch them out of My hand. 29 My Father, who has given them to Me, is greater than all; and no one is able to snatch them out of My Father's hand. 30 I and My Father are one." 31 Then the Jews took up stones again to stone Him. 32 Jesus answered them, "Many good works I have shown you from My Father. For which of those works do you stone Me?" 33 The Jews answered Him, saying, "For a good work we do not stone You, but for blasphemy, and because You, being a Man, make Yourself God." 34 Jesus answered them, "Is it not written in your law, 'I said, "You are gods" '? 35 If He called them gods, to whom the word of God came (and the Scripture cannot be broken), 36 do you say of Him whom the Father sanctified and sent into the world, 'You are blaspheming,' because I said, 'I am the Son of God'? 37 If I do not do the works of My Father, do not believe Me; 38 but if I do, though you do not believe Me, believe the works, that you may know and believe that the Father is in Me, and I in Him."
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In the bolded portion, we get the context in which Jesus invokes the Psalm: to show the Jews who wanted to stone Him that there is precedent in the scriptures for declaring a man to be God, and that He has proven Himself to be so. It was not to say "You are gods, end of story", as though He was simply recalling the verse a propo of nothing. Importantly, the Jews of that time understood Jesus to be making a blasphemous claim about Himself in particular by calling Himself the Son of God, as He explicitly says He has done in verse 36. It is not as though He would've been the first ever to recite that Psalm, after all; rather, the problem for the Mormon invocation of this verse to support their doctrine is that it is understood by all involved to be Jesus claiming that about Himself in a way that goes beyond what any one person could say and remain not a blasphemer, according to first-century Jewish theological and exegetical standards.
Basically, Jesus' theological claim to being the Son of God reflects a fundamentally different reality than does that title when it is found attached to any other people or person. Were that not the case, the Jews would not have sought to stone Him in the first place, just as they didn't stone their own before Him for simply reading or recalling the Psalm in question. So rather than 'proving' that we are all Gods because Jesus said so in the Bible, the full context shows that when Jesus says so about Himself, it means something entirely different. He knows that, His audience (the Jews who were wanting to stone Him) know that, and we know that.
Mormons, unfortunately, don't know that. So they think it means something it does not mean.
(I know you know all this, friend; I write it mainly to try to get the Mormons here to think a bit deeper about what they are presenting as evidence, rather than going on word-search hunts for particular phrases regardless of what they actually mean, as appears to be the case with everything He Is The Way posts.)