score:3
By relinquishing the nationality and passport of one country, under which you were granted a UK visa, and acquiring the citizenship of another, the visa in the surrendered passport would no longer be valid. From your question and comments, you are not a dual national (which would enable you to enter the UK with the passport with the visa). As mentioned, both your former and current nationality require UK visas. However, other than the time and expense to apply, prior visa issuance should be a positive (although no guarantee of success).