1 is not a warbler is it a indigo bunting?
2 really not sure with that dark tail... Magnolia? It feels like a bad guess because that tail pattern should be more obvious but I see white south of the vent and a dark under tail???
3 no idea
I'd go with White-breasted on the nuthatch. The underparts are mostly white, with the typical orangey-rufous color near the vent. Though the apparent orange on the chest would be anomalous if represented correctly, the bill is also too long for Red-breasted. Also, the date would be a useful ID indicator to know for #2.