Some embodiments include an integrated structure having a first opening extending through a stack of alternating insulative levels and conductive levels. A nitride structure is within the first opening and narrows the first opening to form a second opening. Detectable oxide is between the nitride structure and one or more of the conductive levels. Some embodiments include an integrated structure having a conductive material, a select device gate material over the conductive material, and vertically-stacked conductive levels over the select device gate material. A first opening extends through the vertically-stacked levels to the conductive material and has opposing sidewalls along a cross-section. Nitride liners are along the sidewalls of the first opening. Detectable oxide is between at least one of the nitride liners and one or more of the vertically-stacked conductive levels. Some embodiments include methods for forming integrated structures.