Dataset can wrap up a lot of things, but if you have a simple List of Lists inside, you can just do the following and get a Latex array.

Query[TeXForm][Dataset[RandomInteger[{1, 10}, {20, 2}]]]

You can also write out a full TeX document as follows:

Query[TeXForm /* (ExportString[#, "TeX"] &)][
 Dataset[RandomInteger[{1, 10}, {20, 2}]]]

And you can always use Export with a filename instead of ExportString to write out the TeX to a file.

If your Dataset is wrapping something more complicated such as a List of Associations or Association of Associations, I am not sure how TeXForm is going to work. For example, the code below "works" but I don't know enough TeX to know if the output is meaningful.

Query[(1 ;; 5) /* TeXForm][ExampleData[{"Dataset", "Titanic"}]]