Probably not. First of all, exterior products should never be used in interior or confined spaces, so unless your “sunroom” is no more than a screened-in porch, then you definitely should not use it. Secondly, unless the exterior stain specifically states that it can be used on horizontal, trafficked surfaces, it will not perform well on a floor.
Besides, as noted earlier, a stain’s appearance is affected by the underlying wood, so it’s doubtful that the stain will “look” the same on flooring as it does on siding. There are many suitable interior stains on the market which can be tinted to match the color you desire.