You don't say where you are thinking of setting up this company, which might be significant as trade mark law differs slightly between the USA and UK jurisdictions. That said, since Taco Bell operates restaurants in both countries, the issues remain very similar. Unfortunately the UK IPO trade mark database is offline for routine maintenance today and so I can't check exactly what trade marks have been registered and for which classes of goods and sevices. However I think it is safe to assume that they will cover a range of food products including tacos, as well as restaurant and food outlet etc services.
Therefore there would be a large degree of overlap between your taco products and the products for which the Taco Bell mark is registered. This means that sub-sections 10(2)(a) and 10(2)(b) of the Trade Marks Act 1994 would apply. And for claim under these sections, the degree of similarity between the disputed mark and the registered mark does not have to be narrow in order for infringement to be proved. Since you would be, in essence, just be reversing the order of the words, I think it is almost certain that Bell's Tacos would be found to infringe the Taco Bell mark. This is despite the fact that section 11 (2)(a) permits the use of an individual's own name. This might apply if you wished to use Bell's as your trading name, but wouldn't extend to the inclusion of the word tacos, even if that was what you were selling. Clearly people would refer to your product as Bell's tacos, but that wouldn't allow you to use that descriptor in your marketing operations. It is perhaps relevant that the 'Bell' in Taco Bell is the name of the company's founder, Glen Bell.
And you would also be highly vulnerable to a parallel claim of passing off for which the own-name defence would not be available. In a passing off claim, the primary ingredient is an act of misrepresentation (which doesn't necessarily need to be dishonest) in respect of a trade mark or trading name which has goodwill attached to it. I don't think Taco Bell would have any difficulty in showing they have goodwill in their name, and so it would be merely a matter for them to show that their brand had suffered or was likely to suffer some detrimental effect from your branding. In the UK passing off is a common law tort (as opposed to a statutory tort), but in the USA it is covered by section 1125a of the Lanham Act which forms part of Title 15 of the United States Code which regulates trade matters. On that details you have given, I think a passing off claim against you is also highly likely to be successful.