It would be easiest to say that the green laser is the most visible, followed by the red laser with a lower wavelength, close to orange. However, the situation is not so straightforward. This statement is true for most materials, but not for all types of surfaces, their colours and types of ambient lighting.

EditThis may come as a surprise to some of you, but physically, colors don't actually exist. Colors are nothing more than different electromagnetic radiations of different wavelengths (frequencies). Moreover, our eyesight perceives only a relatively small part of the spectrum.
Edit by
It needs to be explained..

Lasers are made with several wavelengths (colors) of beam. For example, for red lasers of 1mW to 10mW, we use diodes with a wavelength of 635 nm, which is the red with a tinge of orange that is most visible among reds. However, these diodes can only withstand a temperature range of -12 to 45 °C (we discuss the temperature range more in section 8-Lifetime).

For high-power lasers up to 100mW, we use diodes with a wavelength of 650nm, which is a deep red with a similar thermal endurance of -12 to 45°C. We also have HT diodes that can withstand temperatures from -10 to 70 °C but have a different wavelength, for example 655 nm or 658 nm, which is perceived by the human eye as a darker red.

And then there are green lasers with 515 nm, 532 nm and 520 nm HT wavelengths, which are suitable for use in warm environments. What's the difference?

Definitely a big one!  You say a few nanometers, that's not much, but one can only see in the narrow light spectrum of 380~750nm. Outside that range, UV and IR start. So we can only see with our eyes the light that fits in the 370nm range. Within this range we can fit all the colors the human eye can see.
The greatest sensitivity of the human eye is at 555nm which is a bright light green. Then the sensitivity of the eye drops down to the two limits which are UV and IR as shown in the figure.

Please also note the vertical scale - it is divided into multiples (logarithmically). There is indeed a big difference between the visibility of a green laser and a red laser of the same power. The red laser needs to be much more powerful to be seen as well as the green laser, on a medium grey substrate (We discuss the effect of substrate colour in point 3).

Color display of laser beams

In order to faithfully render the colours of laser diodes on a monitor or paper, we always have to make compromises. An RGB monitor can't display 660nm red, 515nm green, (if it's a high-end monitor it can max 650nm red, 540nm green and 450nm blue. No more). It also depends very much on how the printer manages to print the color which converts the RGB (sRGB, Adobe RGB) signal to a CMYK (cyan-C), magenta-M (magenta-M), yellow-Y (yellow-Y) and black-K) signal which is calculated on white paper. And there is a distortion in every method of conversion, whether perceptual or relative colorimetric, where we actually have to "squeeze" a larger space into a smaller one see image. Definitely note the blue numbers of specific wavelengths and their placement completely outside of the commonly used sRGB and Adobe RGB space, not to mention the SWOP CMYK paper representation. Basically, even that image of the visible color space is false...it is color-adapted to the RGB Monitor and is therefore a truncated compromise.

The exception is partially ProPhoto RGB which can display about 90% of the space. But it doesn't have much of a use yet, as no current monitor or camera can yet fully utilize the full range of ProPhoto RGB space. So it is still more of a future RGB space for now.

In conclusion..

With this post I am trying to explain very simply that it is basically impossible to accurately transfer the personal experience of observing a laser beam with the eye. Any capture by photo or video is very inaccurate and confusing. Basically, 50% of the credibility of the image information is lost. However, after more than 20 years of working with laser beams, we know very well which laser to use for what and under what conditions. We are happy to help you with this decision.