I do not know much about Belgian nationality law, but it seems that the non-EEA spouse is expected to reside in Belgium for at least five years (and been married for at least three years) before being making a "nationality declaration", even if married to a Belgian citizen.
S/he also needs to prove knowledge of one of the national languages (Flemish, French or German) and "social integration" (though it is unclear how that is assessed).
Acquisition de la nationalité belge sur base du mariage avec un(e) Belge (art. 12bis. §1, 3°) - In French
The Dutch option that you speak of, as I understand it, is the Surinder Singh route, where you reside in the Netherlands with your non-EEA spouse and then move back to Belgium with your spouse under EU law, not Belgian law. However, that does not provide any advantage for acquiring Belgian nationality, to the best of my knowledge.
EDIT: I think I have found the section of the Code of Belgian Nationality that applies.
Loi modifiant le Code de la nationalité belge afin de rendre l'acquisition de la nationalité belge neutre du point de vue de l'immigration wrote:Art. 12bis. § 1er. Peuvent acquérir la nationalité belge en faisant une déclaration conformément à l'article 15 :
…
3° l'étranger qui :
a) a atteint l'âge de dix-huit ans;
b) et séjourne légalement en Belgique depuis cinq ans;
c) et apporte la preuve de la connaissance d'une des trois langues nationales;
d) et est marié avec une personne de nationalité belge, si les époux ont vécu ensemble en Belgique pendant au moins trois ans, ou est le parent d'un enfant belge mineur ou mineur non émancipé;
e) et prouve son intégration sociale :
- ou bien par un diplôme ou un certificat délivré par un établissement d'enseignement fondé, reconnu ou subventionné par une Communauté ou par l'Ecole royale militaire et qui est au moins du niveau de l'enseignement secondaire supérieur;
- ou bien en ayant suivi une formation professionnelle d'au moins 400 heures reconnue par une autorité compétente, et en ayant travaillé, au cours des cinq dernières années, pendant au moins 234 journées comme travailleur salarié et/ou comme agent statutaire nommé dans la fonction publique ou en ayant payé en Belgique, dans le cadre d'une activité professionnelle indépendante à titre principal, les cotisations sociales trimestrielles dues par les travailleurs indépendants pendant au moins trois trimestres;
- ou bien en ayant suivi un cours d'intégration prévu par l'autorité compétente de sa résidence principale au moment où il entame son cours d'intégration;
Translation of the above via Google Translate wrote:Art. 12a. § 1st. May acquire Belgian nationality by making a declaration in accordance with Article 15:
...
3 ° the foreigner who:
(a) has reached the age of eighteen;
b) and has been legally resident in Belgium for five years;
c) and provide proof of knowledge of one of the three national languages;
(d) and is married to a person of Belgian nationality, if the spouses have lived together in Belgium for at least three years, or is the parent of a Belgian minor child or a minor who is not emancipated;
e) and proves its social integration:
- or by a diploma or certificate issued by an educational establishment founded, recognized or subsidized by a Community or by the Royal Military Academy and which is at least at the level of upper secondary education;
- or having completed a professional training of at least 400 hours recognized by a competent authority, and having worked in the last five years for at least 234 days as a salaried employee and / or as a statutory agent appointed in the public service or having paid in Belgium, as part of a self-employed main activity, the quarterly social contributions due by the self-employed for at least three quarters;
- or having followed an integration course provided for by the competent authority of his principal residence at the beginning of his integration course;
Apparently,
the area that you reside in can impact your nationality declaration application. Also see the
trail guide to Belgian nationality.
I am not a lawyer or immigration advisor. My statements/comments do not constitute legal advice. E&OE. Please do not PM me for advice.