Two columns overlap in table with multirow macro

with slightly corrected your code:

\documentclass{minimal}
\usepackage{multirow,bigdelim}
\usepackage{amssymb}% added

\begin{document}
\begin{tabular}{p{24mm}l p{24mm}l l@{\hspace{-7ex}}l}% changed
\ldelim\{{9}{3mm}[$\mathbb{C}$ Complejos]
    & \ldelim\{{8}{3mm}[$\mathbb{R}$ Reales]
        & \ldelim\{{7}{3mm}[$\mathbb{Q}$ Racionales]
            & \ldelim\{{6}{3mm}[$\mathbb{Z}$ Enteros]
                & \ldelim\{{2}{3mm}[$\mathbb{N}$ Naturales]
                    & $\mathbb{P}$ Primos \\
    &   &   &   &   & Compuestos \\
    &   &   &   &   & \\
    &   &   &   & $\{0\}$   & \\
    &   &   &   &   & \\
    &   &   &   & $\mathbb{Z}^-$ Enteros negativos  &   \\
    &   &   & Fraccionarios             &   & \\
    &   & $\mathbb{I}$ Irracionales     &   &   &   \\
    &   Imaginarios   &   & &   &    \\
\end{tabular}
\end{document}

as tikz picture (edited version):

\documentclass[tikz, margin=3mm]{standalone}
\usetikzlibrary{calc,
                decorations.pathmorphing,%
                calligraphy,% had to be after decorations.pathreplacing
                positioning,
                }
\usepackage{amssymb,bbm}
\begin{document}
    \begin{tikzpicture}[
node distance=0mm and 3mm,
every node/.style = {minimum height=4mm, text depth=0.3ex, inner sep=1pt, align=left},
        BC/.style = {decorate,
                     decoration={calligraphic brace, amplitude=6pt,
                     mirror},
                     very thick,
                     pen colour={red}
                    },
                        ]
\node (n1)                      {$\mathbb{C}$ Complejos};
\node (n2)  [above right=of n1] {$\mathbb{R}$ Reales};
\node (n3)  [above right=of n2] {$\mathbb{Q}$ Racionales};
\node (n4)  [above right=of n3] {$\mathbb{Z}$ Enteros};
\node (n5)  [above right=of n4] {$\mathbb{N}$ Naturales};
\node (n6)  [right=of n5]       {$\mathbb{P}$ Primos \\
                                 Compuestos};
\path   let \p1 = (n1.east),
            \p2 = (n6.north west),
            \n1 = {veclen(\y2-\y1,\x2-\x1)} in
        coordinate[below=\y2-\y1 of n1.east -| n2.west] (c1);
\node (n7)  [above right=of c1 -| n1.east]
                                {Imaginarios};
\node (n8)  [above right=4mm and 3mm of n7.north -| n2.east]
                                {$\mathbb{I}$ Irracionales};
\node (n9)  [above right=4mm and 3mm of n8.north -| n3.east]
                                {Fraccionarios};
\node (n10) [right=of n4]       {$\{0\}$};
\node (n11) [right=of n3 -| n4.east]
                                {$\mathbb{Z}^-$ Enteros negativos};
%
\draw[BC]   (n6.north -| n2.west) -- (c1);
\draw[BC]   (n6.north -| n3.west) -- (n8.south west);
\draw[BC]   (n6.north -| n4.west) -- (n9.south west);
\draw[BC]   (n6.north -| n5.west) -- (n11.south west);
\draw[BC]   (n6.north west) -- (n6.south west);
    \end{tikzpicture}
\end{document}

Lately, I found this easy solution with cases environment

\documentclass{article}
\usepackage{amsmath,amssymb}

\begin{document}

\begin{displaymath}
\mathbb{C}\text{ Complejos} 
\begin{cases}
    \mathbb{R}\text{ Reales} 
    \begin{cases} 
        \mathbb{Q}\text{ Racionales} 
        \begin{cases}
            \mathbb{Z}\text{ Enteros}
            \begin{cases}
                \mathbb{N}\text{ Naturales} 
                \begin{cases}
                    \mathbb{P}\text{ Primos} \\
                    \text{Compuestos}
                \end{cases} \\
                \{0\} \\[2ex]
                \mathbb{Z}^-\text{ Enteros Negativos}
            \end{cases} \\
            \text{Fraccionarios}
        \end{cases} \\
        \text{Irracionales}
    \end{cases} \\
    \text{Imaginarios}
\end{cases}
\end{displaymath}

\end{document}

Define a suitable environment and then follow the stream.

\documentclass[a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[spanish,es-noquoting]{babel}

\usepackage{amssymb}

\newenvironment{textbrace}
 {$\renewcommand{\arraystretch}{1.5}\left\lbrace\begin{tabular}{@{}l@{}}}
 {\end{tabular}\right.$}

\begin{document}

\begin{table}
\centering\small

$\mathbb{C}$ Complejos
  \begin{textbrace}
  $\mathbb{R}$ Reales
    \begin{textbrace}
    $\mathbb{Q}$ Racionales
      \begin{textbrace}
      $\mathbb{Z}$ Enteros
        \begin{textbrace}
        $\mathbb{N}$ Naturales
          \begin{textbrace}
          Primos
          \\
          Compuestos
          \end{textbrace}
        \\
        $\{0\}$ Cero
        \\
        Enteros negativos
        \end{textbrace}
      \\
      Fraccionarios
      \end{textbrace}
    \\
    $\mathbb{I}$ Irracionales
    \end{textbrace}
  \\
  Imaginarios
  \end{textbrace}

\caption{Jerarquía de números}
\end{table}

\end{document}