\documentclass{article}
\usepackage{circuitikz}
\begin{document}

% https://tex.stackexchange.com/a/32843/132144
\begin{circuitikz} \draw

(0,0) node[nand port] (nand1) {}
(-2,1) node[nand port] (nand2) {}
(-2,-1) node[nand port] (nand3) {}

(nand2.out) -- (nand1.in 1)
(nand3.out) -- (nand1.in 2);

\end{circuitikz}

\end{document}

\documentclass{article}
\usepackage{circuitikz}
\begin{document}

% https://tex.stackexchange.com/a/32843/132144
\begin{circuitikz}

\node[nand port] at (0,0) (nand1) {};
\node[nand port] at (-2,1) (nand2) {};
\node[nand port] at (-2,-1) (nand3) {};

\draw (nand2.out) -- (nand1.in 1);
\draw (nand3.out) -- (nand1.in 2);

\node (i0) at (-4,1.3) {$I_0$};
\node (i1) at (-4,0.7) {$I_1$};
\node (i2) at (-4,-0.7) {$I_2$};
\node (i3) at (-4,-1.3) {$I_3$};
\node (o0) at (1,0) {$O_0$};

\draw (i0) -- (nand2.in 1);
\draw (i1) -- (nand2.in 2);
\draw (i2) -- (nand3.in 1);
\draw (i3) -- (nand3.in 2);
\draw (nand1.out) -- (o0);

\end{circuitikz}

\end{document}

Update the sample TeX file
Update the sample TeX file
