React name change when clicking. state

How to do to click on a button for example, I change the name I have in the state. attached code (there are more things like for example the counter that works for me)

import React, { Component } from 'react';
import estilos from '../css/estilos.css'


class Componente extends Component{

    constructor(props){
        super(props)
        this.state = {
          count : 0,
          nombre : "Tiago"
        }
      }
      cnombre = (e) => {
          e.preventDefault(e)
          this.setState((prevState)=>{
              return{
                   nombre : prevState.nombre = "Mariano"

              }
          })
      }

      sumar = (e) =>{
        e.preventDefault()
        this.setState(function(prevState){
            return{
                count : prevState.count + 1
              }     
        })    
      }

      sumar2 = (e) =>{
          e.preventDefault()
          this.setState((prevState)=>{
              return{
                  count : prevState.count + 2
              }
          })
      }

      restar = (e) =>{
        e.preventDefault()
        this.setState((prevState)=>{
            if(prevState.count >= 1){
                return{
                    count : prevState.count - 1
                }
            }    
        })
      }

      resetear = (e) =>{
          e.preventDefault()
          this.setState({count:0})
      }



    render(){

    return(
        <div>

        <a href="#" onClick = {this.sumar} className = "sumar"> Sumar</a>
        <a href="#" onClick = {this.restar} className = "restar"> Restar</a>
        <a href="#" onClick = {this.resetear} className = "reset"> Resetear</a>
        <a href="#" onClick = {this.sumar2} className = "reset"> Sumar de a dos</a>
        <p onClick = {this.cnombre}>Tiago</p>
        <button onClick = {this.cnombre}>Cambiar</button>
          {this.state.count}

        </div>




    )



}



}

export default Componente