Is this CMOS circuit supposed to be an OR or an XOR?
First, I &quot;markup&quot; your circuit drawing with logical element regions (two inverters, three NANDs):

Then redraw it as digital circuits are drawn:



simulate this circuit &ndash; Schematic created using CircuitLab
and calculate the output:
NANDA outputs \$\overline{A · \overline{B}}\$
NANDB outputs \$\overline{\overline{A} · B}\$
NAND_OUT outputs \$\overline{\left(\overline{A · \overline{B}}\right) · \left(\overline{\overline{A} · B}\right)} = \overline{\left(\overline{A} + B\right) · \left(A + \overline{B}\right)} = \overline{\overline{A} · \overline{B} + A · B} = {A⊕B}\$