@Pingi Some examples code have this lines of code:
I commented because the library could be bad.

void setup(void) {
  Serial.begin(115200);
  Serial.println("Hello!");

  nfc.begin();

//  uint32_t versiondata = nfc.getFirmwareVersion();
//  if (! versiondata) {
//    Serial.print("Didn't find PN53x board");
//    while (1); // halt
//  }
//  
//  // Got ok data, print it out!
//  Serial.print("Found chip PN5"); Serial.println((versiondata>>24) & 0xFF, HEX); 
//  Serial.print("Firmware ver. "); Serial.print((versiondata>>16) & 0xFF, DEC); 
//  Serial.print('.'); Serial.println((versiondata>>8) & 0xFF, DEC);

Try the same that I did! Read my previous reply. I made it work.

I already tried with that libraries without success. My only interest was to make it work with I2C mode so, the tutorial fits perfect for me. I also read on internet that all libraries where not necesaries, just only 2 on my case.

From internet I found people that make it work doing some of one of the step that i did.
Example: reset the button, removing firmware lines of code, changing voltage source from 5v to 3.3V.

Perhaps, libraries where not my problem, I not isolated the real problem.
Perhaps the problem is the combination of chinese arduino nano V3.0 with elechouse nfc reader V2.0.
It's cost me a lot of investigation to make it work with that combination.

My next step is comunicate nfc readings with my raspberry trought arduino. :D

I could make it work.(sorry from my english..I am an uruguayan native :) )
I took my libraries from this tutorial:
http://www.instructables.com/id/NFC-Ring-Lock-Box/
Also , this are some steps that i did:

• I asigned read/write permissions to arduino libraries folder.
• Just put on libraries the same from tutorial
• I changed the conexion pin to 3.3V , not 5V from arduino to nfc reader.
• Before upload the code, y pressed arduino nano reset button some seconds!, after that y upload the code.
• I modified the code removing that was not required.
  Its seems that the lines thats gets the firmware doesn´t work.

This is the code( i don´t wnow hoy to formatead it)

#include <Wire.h>
#include <PN532_I2C.h>
#include <PN532.h>

PN532_I2C pn532i2c(Wire);
PN532 nfc(pn532i2c);

void setup() {
  Serial.begin(115200);
  Serial.println("Hello!");
  nfc.begin();
  nfc.SAMConfig(); // configure board to read RFID tags
  Serial.println("Waiting for an ISO14443A card");
}

void loop() {
  String ringUid;
  boolean success;
  uint8_t uid[] = {0, 0, 0, 0, 0, 0, 0}; // Buffer to store the returned UID
  uint8_t uidLength; // Length of the UID (4 or 7 bytes depending on ISO14443A card type
  
  success = nfc.readPassiveTargetID(PN532_MIFARE_ISO14443A, &uid[0], &uidLength);

  if (success) {
    Serial.println("Found a card!");
    Serial.print("UID Length: ");
    Serial.print(uidLength, DEC);
    Serial.println(" bytes");
    Serial.print("UID Value: ");

    for (uint8_t i=0; i < uidLength; i++) {
      Serial.print(" 0x");
      Serial.print(uid[i], HEX);
      ringUid += String(uid[i], HEX);
    }

    Serial.println("");
    // Wait 1 second before continuing
    delay(1000);
  }
}

(edit) indent express train ran by @andreas

I have the same issue. I am trying to conect a elechouse PN532 NFC module V3 to arduino nano and nothing. Same problem. Only says "hello".

@Lokki I bought one of these for mi Raspberry pi 2. I would like to know how to conect to it.
What would be an easy way? Perhaps with a TTL to USB cable directly to a usb raspberry port?
I am newbie :D